Acronyms

This page provides a list of acronyms commonly used with MOTOTRBO and/or DMR, along with their meanings and, where available, links to their respective Wiki pages.

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4FSK

4FSK modulation

4FSK is a constant-envelope modulation technique used in DMR and defined in ETSI TS102 361-1. DMR transmissions are sent at 4,800 symbols per second. Each symbol represents two binary bits (dibits) and each of these symbols has a certain deviation from the transmitter center frequency ($f_{c}$).

A

AB

Appended Blocks (AB) specifies the number of data blocks that follow a Protocol Data Unit (PDU) header in packet data or Unified Data Transport (UDT) transmissions.

ACK

Acknowledgement (ACK) is a positive response used to confirm that one or more data blocks or packets have been successfully received by the recipient.

ACKD

Outbound acknowledgement (ACKD) is a positive acknowledgement response transmitted from the Trunked Station (TS) to a radio on the outbound channel.

ACKU

Inbound acknowledgement is a positive acknowledgement response transmitted from a radio (MS) to the Trunked Station (TS) on the inbound channel.

AD

Appended Data (AD) refers to the information content carried within the data blocks that are attached to a UDT header.

ADRNULL

ADRNULL (Null Address) is a reserved address (00000016) that is not assigned to any entity and is often used to fill unused address fields or represent an invalid destination.

ADVPN

ADVPN (Auto-Discovery VPN) is a technology that allows fixed network equipment in a hub-and-spoke network to communicate directly with each other without routing all their traffic through the central data center. It combines the management simplicity of a hub-and-spoke model with the performance of a full-mesh network.

See also DMVPN.

ADK

The Application Development Kit (ADK) is a set of technical resources, protocol specifications, and guidelines that allow third-party developers to create custom hardware and software solutions for the MOTOTRBO digital radio ecosystem.

It is a collection of tools and documentation that covers the following:

• The Option Board ADK is used to develop software for internal option boards (small hardware modules installed inside the radio). This allows the radio to perform local processing for special features not supported by the radio.
• The Text Messaging ADK describes the protocols needed to send and receive text messages or job tickets between a computer application and radio users.
• The Location Data ADK describes how to extract GNSS data and presence information from radios for fleet tracking and dispatch software.
• The XCMP-Based Peripheral ADK describes how to use the Extended Command and Management Protocol (XCMP) to allow external devices (e.g. a laptop or a barcode scanner) to control the radio via USB or Bluetooth.
• The Telemetry ADK can be used for monitoring and controlling external hardware, such as remotely opening a gate or triggering an alarm when a sensor state changes.

To enable these customizations, the ADK utilizes several underlying Motorola technologies:

• XCMP (Extended Command and Management Protocol) is the primary language used to send commands to the radio (e.g., "change channel," "send alert," or "display text on screen").
• XNL (XCMP Network Layer) is the transport protocol that ensures these commands reach the correct component, whether it’s an internal module or an external PC.
• Network Interfaces allows developers to interface with the system at the Subscriber level (connecting to a single radio via USB/Bluetooth) or the System level (connecting directly to repeaters or a system gateway like MNIS).

AH

Ahoy is a PDU (either C_AHOY or P_AHOY) sent by the system that queries a radio and demands an immediate response to confirm its presence or readiness.

AI

Air Interface refers to the radio communication protocol that defines the physical and data link layers for interaction between DMR devices.

The DMR AI Protocol Layers

The DMR protocol stack, which outlines the different layers of communication, includes three layers:

• The Physical Layer (Layer 1) deals with the physical burst, composed of bits, that is sent and received, covering functions like modulation, demodulation, and RF characteristics.
• The Data Link Layer (Layer 2) is responsible for medium access control, channel management, framing, and link addressing, and handles the interfacing of voice applications (vocoder data) and data bearer services with the Physical Layer.
• The Call Control Layer (Layer 3) is part of the control plane (C-plane) and is responsible for call control, addressing, and providing services supported by DMR, including Short Data and Packet Data services.

The Air Interface also defines how user numbering and dial strings are mapped to the AI address space for individual and group calls.

AL

Accept Leader is a procedure in TDMA direct mode where a radio resolves a conflict by accepting another unit as the timing leader for the channel.

ALLMSID

ALLMSID is a special talkgroup identifier (FFFFFF16)  used to address every radio registered across the entire DMR Tier 3 network.

ALLMSIDL

ALLMSIDL is a local identifier (FFFFFD16) used to address all radios on a single radio site, of a DMR Tier 3 system, where the call was initiated.

ALLMSIDZ

ALLMSIDZ is an identifier (FFFFFE16) used to address all radios within a specific subset of radio sites in a DMR Tier 3 system.

ALS

Ambient Listening Service (ALS) is a specialized individual voice call that forces the target radio to transmit its microphone audio without notifying the user or requiring a PTT press. In MOTOTRBO radios, this is known as Remote Monitor.

AMBE 2+™

AMBE 2+™ from DVSI Inc. is the standard vocoder technology used by all DMR manufacturers to compress and decompress speech data for transmission.

ANL

Announce New Leader (ANL) is a procedure used in TDMA direct mode wide area timing when a Mobile Station detects it needs to appoint a new timing leader.

Ann_WD_TSCC

Ann_WD_TSCC stands for Announce/Withdraw TSCC and is a system announcement used to add or remove control channels from the radio’s hunt list.

AP

Absolute Parameters (AP) MBC continuation blocks, such as CG_AP or VN_AP provide absolute transmitter and receiver frequency details for channel grants or voting.

API

See Application Programming Interface.

APP

An Analogue Phone Patch is a legacy commercial off-the-shelf hardware device used to connect a MOTOTRBO repeater to an analogue (PSTN/POTS/FXO) phone line to half-duplex voice communication between radio users and phone callers.

The Analogue Phone Patch is physically connected to a MOTOTRBO repeater via a 4-wire interface using the repeater's backplane GPIO connector.

In addition to telephone interconnectivity, it provides essential signaling and management functions, such as Access and De-access Codes to authorized users, Time-Out Timers (TOT) to manage call duration, and go-ahead tones to notify phone users when they can begin speaking.

ARP

The Address Resolution Protocol (ARP) is a networking protocol used to map a dynamic IP address (Layer 3) to a fixed physical MAC address (Layer 2) on a local area network (LAN). While an IP address tells the network where a device is logically located, the MAC address is the actual hardware ID needed to deliver data to that specific device's network interface.

When a MOTOTRBO repeater (A) wants to send data to another repeater (B) on the same network, it knows the other repeater's IP address (see LE) but not its MAC address. Repeater A first checks its own ARP cache to see if it already knows the mapping. If it does, it sends the data immediately. If the address isn't in the cache, repeater A sends an ARP request packet to every device on the network. This message essentially asks: "Who has the IP address 192.168.1.5? Please tell 192.168.1.4." Every device receives the request, but only repeater B (which has 192.168.1.5) responds, saying: "192.168.1.4 is at D4:36:39:F4:0D:4E." Repeater A saves this mapping in its ARP cache for future use and proceeds to send the actual data packet.

See also Address Resolution Protocol.

ARS

Automatic Registration Service (ARS or sometimes referred to as the Presence Notifier) is a MOTOTRBO system feature that enables a radio to automatically register with a server-based data application when it powers up or switches to a data-capable channel. This information helps applications determine whether a given radio is present before attempting to request or send data.

ARTS

Auto-Range Transponder System (ARTS) is a feature available in MOTOTRBO radios when operating in analogue mode. It is designed to inform users when their radio is out of range from other units which also have ARTS enabled.

An ARTS system uses automatic polling, where a radio transmits a signal once every 25 or 55 seconds to "shake hands" with other ARTS-equipped radios.

When a radio receives an incoming ARTS signal, it sounds a short tone and displays an "In Range" message. If the radio fails to receive a signal for more than two minutes, it sounds a tone and displays an "Out of Range" message.

A radio with ARTS can be configured to operate on one of three modes: Transmit Mode (sends polling signals only), Receive Mode (receives signals to notify the user of status), and Transmit and Receive Mode (does both).

AT

Access Type is a bit in the Common Announcement Channel (CACH) that indicates if the inbound channel is busy or idle to regulate random access.

ATEX

ATEX (from the French ATmosphères EXplosibles) refers to a set of European Union safety directives designed to ensure that equipment used in hazardous environments cannot cause an explosion.

When a radio is ATEX-certified, it is intrinsically safe, meaning it is engineered to operate without producing enough electrical or thermal energy to ignite flammable gases, vapors, or dust in the air, depending on the certification level.

See also ATEX.

Auth

In DMR Tier 3 networks, Authentication (Auth) is a procedure to verify the identity of a device through a challenge-and-response algorithm using a shared (secret) 128-bit key.

AUTHI

Authentication Identifier (AUTHI) is a specific gateway address (FFFECD16) used in DMR Tier 3 systems to manage authentication service requests.

AVPN

AVPN stands for AutoVPN. This is a protocol used on networking equipment in MOTOTRBO Capacity Plus Multi Site and Capacity Max systems for creating secure overlay networks.

See also ADVPN and DMVPN.

AW_FLAG

Announce/Withdraw Flag is a bit in the system announcements (specifically AW_FLAG1 and AW_FLAG2) that dictate whether an announced channel is being added to or removed from the hunt list in a DMR Tier 3 system.

B

BC_AP

Broadcast Absolute Parameters (BC_AP) is an appended Multiple Block Control (MBC) Packet Data Unit (PDU). It functions as a continuation block within the multi-block PDU to specify absolute the transmitter and receiver frequencies. This is only used on DMR Tier 3 systems and there appears to be no implementations of this.

BCD

BCD (Binary Coded Decimal) BCD formatting is used for encoding specific types of data, particularly dialled digits. This includes the extended address information when communicating through various gateways, such as those for PABX, PSTN, LINEI, or DISPATI services. When appended data is BCD coded, up to 92 BCD digits may be transported

BER

BER (Bit Error Rate) is a metric used to describe signal quality and is stated as a percentage.

BF

BF (Blocks to Follow) is an information element that specifies the number of blocks in a packet, excluding the first header block. This element has a length of 7 bits. The value of BF is used to calculate the actual number of user data octets for various data coding rates, including rate ½, rate ¾, and full rate coded data as well as for both confirmed and unconfirmed data types.

BFM

BFM stands for IMPRES Battery Fleet Management. This is an application that gathers and reports IMPRES battery data.

See IMPRES Battery Fleet Management.

BGP

BGP (Border Gateway Protocol) is a routing protocol which can be used in MOTOTRBO Capacity Max systems as a routing protocol when IPsec is not used and only GRE tunnelling is employed. It can also be used in Capacity Plus Multi Site systems where it would be used between site routers and customer network routers to ensure communication.

BLE

BLE or BTLE (Bluetooth Low Energy) is a power-conserving variant of Bluetooth technology designed for short-range wireless communication. It is specifically engineered for applications where low power consumption is needed. In MOTOTRBO systems, it is used to provide location-based information when GNSS is not available or cannot be used.

iBeacon is Apple's implementation of Bluetooth Low Energy wireless technology. MOTOTRBO systems support iBeacon, although other non-Apple beacons exist in the market. BLE Beacons are manufactured by third-parties like Estimote, Roximity, and Gimbal.

Also see Bluetooth.

BMP

BMP (Basic Multilingual Plane) is a term related to character encoding, specifically within the context of UTF-16BE. Text messaging in MOTOTRBO systems is designed to utilize UTF-16BE character encoding in plane 0, which is known as the Basic Multilingual Plane or BMP.

BOC

BOC (Beginning Of Call) signifies the initiation of a communication session.

For a talkgroup call, the BOC follows a predetermined channel access mechanism. However, for individual calls, BOC can occur through two defined call setup methods: Press And Talk Call Setup (PATCS) or Off Air Call SetUp (OACSU).

The first burst at the Beginning Of Transmission (BOT), which may be the BOC, carries the necessary information to notify the selected group of the call. Similarly, in the PATCS method for individual calls, the first burst at the BOT, which may be the BOC, carries the information required to notify the target radio of the incoming call.

Also see; PATCS; OACSU and BOT.

BOR

BOR (Beginning Of Receive.) is an event or primitive within the DMR protocol that signifies the initiation of a reception at a Base Station (BS).

BOR events cause High Level Base Station (BS) state transitions. For example, upon receiving a burst, a BS may transition from a Channel_Hangtime state to a Repeating_Slot state for a single slot, or to a Repeating_Both_Slots state if activity is detected on both slots.

When the BS receives a burst, such as a Voice_LC_Header or a Control Signalling BlocK (CSBK), a BOR primitive is sent to the Call Control Layer (CCL) process, indicating that the BS should start repeating the inbound traffic.

Upon a valid "wakeup message" (which triggers a receive event), the BS initiates a Mobile Station Inactivity Timer (T_MSInactiv). BOR, as a receive event, also influences the behavior of channel hangtime, where the reception of bursts (BOR) transitions the BS into a repeating state.

BOT

BOT (Beginning Of Transmission) refers to the initial burst or signal sent when a radio begins transmitting. The key difference and relationship between BOT and BOC is that the first burst at the Beginning Of Transmission (BOT) may be the Beginning Of Call (BOC). This means that the BOC is a specific instance or a type of BOT that signifies the initiation of a call. In essence, BOT is the general act of starting a transmission, while BOC is the specific moment a communication session (a call) is initiated, and this initiation often coincides with the very first transmission burst.

BPTC

BPTC (Block Product Turbo Codes) is a Forward Error Correction (FEC) mechanism used in DMR systems - including MOTOTRBO - to provide robust error protection for various data and control signals during over-the-air transmission.

BPTC aims to improve data communication performance and reliability by enabling the detection and correction of errors in transmitted information and is a core component of DMR Air Interface Layer 2 Protocol Data Units (PDUs).

BR

In some literature, BR is an abbreviation commonly used in system diagrams and refers to a Base Repeater or Base Radio (though the latter is only really used in conjunction with TETRA).

BS

A Base Station (BS) is fixed end equipment that is used to offer DMR services to radio (MS). A Repeater or Base Repeater (BR) would be part of the Base Station though BS refers to the repeater plus any site controller - in the case of DMR Tier 3.

BTV_GRANT

BTV_GRANT (Broadcast Talkgroup Voice Channel Grant) is a type of Control Signalling Block (CSBK) or Multi Block Control (MBC) Protocol Data Unit (PDU). On a DMR Tier 3 system like MOTOTRBO Capacity Max, the Trunk Station (TS) transmits the BTV_GRANT PDU to announce a new call on a payload channel or to grant a channel for a broadcast talkgroup voice call. This PDU is sent without expecting a response.

A BTV_GRANT PDU includes the Logical Physical Channel Number; Logical Channel Number (timeslot); Late Entry Flag; Emergency Flag; Offset (Specifies whether the payload channel uses aligned or offset timing); Source and Destination Addresses. Like other DMR data and control signals, BTV_GRANT PDUs are protected using Block Product Turbo Codes (BPTC) for error correction. The PDU can be transmitted on the Trunk Station Control Channel (TSCC) or a payload channel (a.k.a. Trafiic Channel).

C

CA

Certificate Authority (CA) is a server or entity involved in Certificate Management, which Wi-Fi capable MOTOTRBO devices support through the Simple Certificate Enrollment Protocol (SCEP). Certificate Management operations include supporting RSA-based X.509 V3 certificates, downloading CA certificates, and client certificate enrolment and auto-renewal.

CACH

Common Announcement Channel (CACH) is a component of the outbound channel in DMR systems. The CACH is defined between outbound bursts and is used for channel management (framing and access) and low-speed signaling. It continuously transmits on the outbound channel, even when there's no information to send. Its purposes include indicating the usage status (idle or busy) of the inbound time slot, which is delayed by one slot to allow the receiver time to decode and react. It also indicates the channel number for both inbound and outbound time slots. The CACH carries a Short Link Control message with a 28-bit information field, protected by a block product turbo code (BPTC).

CAI

Call User Address Identity (CAI) refers to a network assignment for radios, specifically related to IP addresses. Radios have multiple CAI IP addresses (Internal, External, and Bluetooth Network Addresses), which are Class A addresses using network IDs such as CAI Network, CAI Network+1, and CAI Network+2. The default CAI Network setting uses Class A network IDs of 12, 13, and 14. It's recommended to use the default value unless it conflicts with other devices on the customer's network, and if changed, all MOTOTRBO radios in the system must be updated with the same parameter.

CBF

CBF (CSBK Blocks to Follow) is an information element with a length of 8 bits that is part of the Preamble CSBK PDU (Pre_CSBK). Its purpose is to indicate the number of Preamble CSBK PDUs and either the following Control Signalling Block (CSBK) or data message that will be sent. It is important to note that the CBF value does not include the current preamble block itself in its count.

The Pre_CSBK PDU, which contains the CBF, can be used to increase the robustness of non-voice (data, CSBK, etc.) delivery for scanning radios or to improve battery life by implementing a sleep mode.

The concept of "Blocks to Follow" is also a general element within data packet headers, indicating the number of blocks in a packet, excluding the first header block. For Multi Block Control (MBC) messages, which are used when a single CSBK cannot carry all necessary control information, they consist of a header, intermediate blocks, and a last block, with the "Blocks to Follow" field being needed for reassembly.

CC

CC (Colour Code) is an element in DMR systems, primarily used for channel identification and interference management. A Colour Code is an information element and a channel attribute that is assigned to radios and channels. It is a numerical identifier, typically ranging from 0 to 15 (00002 to 11112). In dual capacity direct mode channels, Colour Code 15 is reserved. It is present in the embedded signalling field and general data bursts. Crucially, the Colour Code is not used for addressing individual or group calls. Its function is distinct from group IDs, which are used to separate users into groups.

The main purpose of a Colour Code is to provide a simple means of distinguishing overlapping radio sites, particularly to detect co-channel interference. It uniquely identifies systems or channels that operate on common frequencies. This helps prevent radios from interfering with or listening to traffic from an unintended system operating on the same frequency. It can also be combined with a "prefix" to differentiate between various system operators using shared channels.

CCE

CCE (CT_CSBK Evaluation) refers to a process in DMR systems where Dual Capacity Direct Mode (DCDM) and wide area timing are used.

During CT_CSBK Evaluation, a radio examines the information elements contained within a Channel Timing CSBK (CT_CSBK) message. These elements include the Leader Dynamic Identifier (LDI), Leader Identifier (LID), Generation (Gen), Sync Age (SA), Channel Timing Opcode (CTO), New Leader (NL), Source Dynamic Identifier (SDI), and Source Identifier (SID). The radio then Determines Channel Slot Timing; Decodes Misaligned Transmissions and Initiates Further Actions such as Sending a correction (SC); Accepting a leader (AL); Appointing a new leader (ANL) or Performing a timing push (TP).

CCL

The Call Control Layer (CCL) represents Layer 3 of the DMR Air Interface protocol stack and lies within the Control Plane (C-plane). The CCL is responsible for the control of calls, including addressing and managing features and facilities. It provides the various services supported by DMR and explicitly supports Short Data and Packet Data services. Key functions of the CCL include; establishing and terminating voice and data calls; managing destination addresses as well as managing available resources and access requests.

CG

The Channel Grant Protocol Data Unit (PDU), often known as P_GRANT, is transmitted by the Trunk Station Control Channel (TSCC) on a DMR Tier 3 system. The main purpose of a Channel Grant is to announce a new call on a payload channel or to swap an existing call to a different replacement channel. The TSCC continuously transmits Channel Grant PDUs for active talkgroup calls to allow radios to join a call that is already in progress (late entry).

For Off Air Call Set-Up (OACSU) calls, Channel Grant PDUs are not sent until the called party accepts the call.

The system uses a Channel Grant Waiting Timer, typically 15 seconds (configurable from 4 to 60 seconds), which specifies the maximum time a radio waits for its channel grant after an initial response. A Channel Grant PDU can be transmitted as a single block Control Signalling Block (CSBK) or a Multi Block Control (MBC) PDU, with Channel Grant Absolute Parameters (CG_AP) providing absolute transmitter and receiver frequencies when appended as an MBC PDU.

CG_AP

In ETSI TS 102 361-4, CG_AP stands for Channel Grant Absolute Parameters. It refers to a Protocol Data Unit (PDU) that serves as an appended Multi Block Control (MBC) PDU.

The primary function of CG_AP is to specify the absolute transmitter and receiver frequencies. This is particularly relevant when a Channel Grant (P_GRANT) PDU, which announces a new call or a channel swap, indicates that absolute frequencies are to be defined in a subsequent block, often when the logical channel number is set to 4095. The CG_AP PDU contains specific information elements, such as those related to the CdefParms (Channel Definition Parameters), including the Logical Physical Channel Number, Absolute transmitter frequency - integer MHz, and Absolute transmitter frequency - kHz. The CSBK Opcode of the CG_AP PDU will match that of the initial MBC block (the Channel Grant) to which it is appended.

CH

In MOTOTRBO Capacity Max and DMR Tier 3 systems, CH means Channel. In MOTOTRBO Capacity Max and DMR Tier 3, a Channel Number (also called Channel ID) is a logical entity, ranging from 1 to 4094, used to represent this mapping over-the-air.

Channels can serve different purposes within a system:

1. Traffic channels carry speech or data information.
2. Control channels (like the Trunk Station Control Channel, TSCC) are dedicated or composite channels used for system management, broadcasting parameters, and handling access requests from Mobile Stations (MSs).
3. Revert Channels (e.g., Data Revert Channels, Enhanced GPS Revert Channels) are designated channels for offloading data messages from radios to a server, increasing supported call load without impacting trunked channels.

The system automatically assigns physical channels in DMR Tier 3 systems, and MSs and Trunk Stations (TSs) must agree on the Colour Code allocated for each physical channel. Control Channel hunting procedures involve MSs searching through candidate physical channels to find an appropriate TSCC

CH_ADJ

In MOTOTRBO and DMR systems, CH_ADJ stands for Physical Channel Number of the Adjacent Site to be assessed. It is an information element within a Broadcast Adjacent Site Information PDU, which is part of the Network System Announcements transmitted by a Trunk Station Control Channel (TSCC). This PDU announces information about TSCCs (Trunk Station Control Channels) in use on radio sites in the vicinity of the current TSCC.

The purpose of CH_ADJ is to assist Mobile Stations (MSs) in acquiring an appropriate control channel if the radio moves out of radio contact with the current TSCC. A radio can use the physical channel number (CH_ADJ) received in the Adjacent Site PDU to modify its TSCC search, prioritizing radio channels that are more likely to provide a satisfactory service. The value of CH_ADJ ranges from 1 to 4095

CH_VOTE

In MOTOTRBO Capacity Max and DMR Tier 3 systems, CH_VOTE refers to the logical or physical channel number of an adjacent site's Trunk Station Control Channel (TSCC) that Mobile Stations (MSs) are invited to assess. It is an information element contained within a Vote Now Advice PDU, which is a type of Network System Announcement broadcast by a TSCC.

The primary function of CH_VOTE is to encourage idle MSs to evaluate the signal quality of an alternative TSCC in the vicinity, potentially for improved service. This element is 12 bits in length and can range from 1 to 4095.

If the CH_VOTE value is between 1 and 4094, it represents a logical channel number which maps to a specific pair of physical transmit and receive frequencies. However, if the CH_VOTE value is 4095, it indicates that the absolute transmitter and receiver frequencies of the TSCC to be assessed are defined in a subsequent, appended Multi Block Control (MBC) PDU called Vote Now Absolute Parameters (VN_AP).

CHNULL

In MOTOTRBO Capacity Max and DMR Tier 3 systems, CHNULL is an identifier that specifically refers to a logical physical channel that is not assigned. Its hexadecimal value is 00016. This identifier is used in signalling, for example, within the Announce/Withdraw TSCC PDU, to indicate that a particular broadcast channel (such as BCAST_CH2 or BCAST_CH1) is unassigned or not in use.

CLI

In MOTOTRBO Capacity Max and DMR Tier 3 systems, CLI (Caller Line Identity) refers to the ability to view the calling party's number before answering the telephone. CLI information can be transported outbound from the system, specifically for calls originating from PSTN (Public Switched Telephone Network), PABX (Private Automatic Branch eXchange) line, and dispatcher gateways to the called Mobile Stations (MSs). For instance, a Trunk Station Control Channel (TSCC) might download CLI information to the recipient as part of a call setup from the PSTN. CLI is also listed as a type of Short System Data among TSCC outbound Protocol Data Units (PDUs).

CMB

CMB (Capacity Max Bridge) is a software application that resides on the Capacity Max System Server (CMSS) that can bridge supported call types between the Capacity Max System and a MOTOTRBO Connect Plus system. It functions as a client application of the MNIS Voice and Radio Command (VRC) Gateway, sharing its IP address. This facilitates a smooth and phased migration from Connect Plus to Capacity Max.

It requires a Capacity Max Bridge license for operation, which can be configured in offline (default) or online modes, with the latter involving communication with a licensing server. If operating in online mode and communication with the licensing server is lost, a grace period of up to 30 days is provided before bridging operations cease.

CMSS

A CMSS (Capacity Max System Server) is a core computing platform in a MOTOTRBO Capacity Max trunked radio system. It uses a Motorola Solutions industry standard server that hosts a set of virtual machines or containers running essential system applications.

The primary purpose of the CMSS is to manage the overall operation of the Capacity Max system, with at least one licensed CMSS being a mandatory requirement for system deployment. It also holds the licenses for other elements of the system, such as VRC Gateways.

The CMSS comes pre-installed with several key software appliances, which are required for system functionality:

• The Trunking Controller (TC), which is responsible for the overall management of the Capacity Max system.
• The MNIS Voice and Radio Command (VRC) Gateway, which enables wireline voice applications like voice dispatch, voice recorders, and telephone gateways to communicate with the Capacity Max radio system over an IPv4 network.
• The System Advisor (SA) server, providing fault management, system, and call monitoring solutions, including logging device status, alarms, and call activity.
• The Enhanced Software Update (ESU), used for CMSS maintenance tasks (i.e. upgrades).
• The Capacity Max Bridge (CMB), a software application that bridges supported call types between a Capacity Max System a MOTOTRBO Connect Plus system.

For full operation, each hosted component on the CMSS must be individually licensed. The CMSS is configured using Radio Management (RM). It is designed for high availability, supporting up to five CMSS instances for redundancy, including both physical and geographical redundancy, to ensure continuous service even in the event of a server or network failure. The IP addresses for its virtual appliances are automatically derived with fixed offsets from a configurable base IP address, and it utilizes a CMSS Gateway Network for external application interfaces.

The CMSS is supplied by Motorola Solutions in a fully functional state. No software needs to be installed before deployment. It is not possible to "install" the software on a customer-owned server.

COG

COG (Course Over Ground) is an information element included in GNSS data as part of a USBD Poll Response PDU for Location (LIP) Service. The COG value indicates the direction of travel in degrees, ranging from 0 to 359. MOTOTRBO Capacity Max is the only system topology which supports LIP. The other network topologies only support LRRP.

ContCAT

ContCAT (Control Category) refers to a classification assigned to a radio and stored in its codeplug. There are two available control categories, designated as A and B. The primary purpose of the Control Category is to govern the acquisition and retention of a Trunk Station Control Channel (TSCC) in a DMR Tier 3 system. This is done via the PAR sub-field within the System Identity Code (C_SYScode), which is continuously transmitted over the TSCC. The PAR sub-field explicitly indicates which radio control categories are permitted to become active on that TSCC.

When a radio attempts to acquire a TSCC, it reads the C_SYScode and examines the PAR sub-field in conjunction with its own assigned Control Category (ContCAT). If the MS's control category is not permitted access by the PAR sub-field value, the radio will assume it is not authorized to acquire that particular TSCC.

C-plane

C-plane or Control plane is a part of the DMR protocol stack that is dedicated to control and data services. It handles signalling with addressing capability.

The C-plane lies above the Physical Layer (Layer 1) and is interconnected with the Data Link Layer (DLL, Layer 2) and the Call Control Layer (CCL, Layer 3). The Call Control Layer (CCL), which is Layer 3, resides in the C-plane. It is responsible for call control (addressing, facilities/features) and provides the services supported by DMR, including Short Data and Packet Data service.

The Control Plane is distinct from the User plane (U-plane), which is dedicated to user voice services. While the U-plane requires a regular physical link for constant delay services (circuit mode), the C-plane needs only a discrete or non-continuous physical link to pass information, although it needs a continuous virtual link to support the service (signalling or packet mode service).

The Control Plane is responsible for:

• Call Control: Establishing, maintaining, and terminating calls.
• Addressing: Managing destination addressing (DMR IDs or gateways).
• Services: Providing DMR services and supporting intrinsic services like emergency signalling, pre-emption, and late entry.
• Data Services: Supporting Short Data and Packet Data services.
• Signalling: Exchanging signalling and/or user data with the call control layer, and handling announcement signalling.
• Resource Management (in Tier III systems): Managing control channel resources via random access protocols and queuing for payload resources.
• Location Management: Supporting MS location information through registration.
• System Parameters: Broadcasting system parameters to radio subscriber terminals.

CPS

See Customer Programming Software.

CPMS

Capacity Plus Multisite; Multisite Capacity Plus or Linked Capacity Plus is a Motorola Solutions proprietary trunking system topology that is based on DMR. For more information, see Multisite Capacity Plus.

Also see Capacity Plus.

CPSS

Capacity Plus Single Site or just Capacity Plus is a Motorola Solutions proprietary trunking system topology that is based on DMR. For more information, see Capacity Plus.

Also see Multisite Capacity Plus.

CRC

CRC (Cyclic Redundancy Checksum) is a mathematical checksum technique used for data error detection. Its primary purpose is to enable the receiver to validate the integrity of a received message and to determine which, if any, bits have been corrupted. This allows the receiver to correct bit errors that may have occurred due to radio frequency channel impairment. ETSI TS 102 361 utilizes several types of CRC with varying lengths and calculation methods for different purposes.

CS

CS (Checksum) refers to a 5-bit Checksum used in DMR Link Control (LC) messaging.

CSBK

CSBK (Control Signalling Block) is a fundamental element of the DMR Air Interface. It is mostly used for control signalling but play a role in error detection. CSBKs are crucial for various system operations, including managing the acquisition and retention of a Trunk Station Control Channel (TSCC). A CSBK message contains a 96-bit information field, comprising 80 bits for signalling and 16 bits for the CRC. It typically includes 8 octets of data, associated with a CSBK Opcode (CSBKO) and a Feature ID (FID) combination. The CSBK is protected by a Block Product Turbo Code (BPTC) Forward Error Correction.

CSBKO

In ETSI TS 102 361, the Control Signalling Block Opcode (CSBKO) is a 6-bit information element found in Octet 0 of the Control Signalling Block (CSBK) Protocol Data Unit (PDU). Its primary purpose is to identify the specific type of control signaling or data service being transmitted "over-air" within a "facility set" defined by the Feature ID (FID). The CSBKO replaces the Full Link Control Opcode (FLCO) in various CSBKs, including those for channel grants, announcements, random access, acknowledgements, and more. Examples of functions identified by CSBKO include:

• Activation/Requests: Base Station Outbound Activation, Unit to Unit Voice Service Request/Answer Response.
• Channel Management: Channel Grant PDUs (for private voice/data, talkgroup voice/data, duplex), Move TSCC, Channel Timing CSBK.
• System Control: Aloha (random access management), Announcements, Ahoy (enquiry for MS response), Clear (call clearing), Protect (channel protection), Maintenance.
• Data Transport: Unified Data Transport (UDT) Headers, Unified Single Block Data (USBD).
• Responses: Negative Acknowledge Response, various Acknowledgements.
• Other: Preamble CSBK (for robustness/battery life).

While CSBKO specifies the function, it's often used in conjunction with a Feature ID (FID) which typically defaults to $00000000_{2}$ for standard CSBKs.

CSQ

CSQ (Carrier Squelch) is a setting in all MOTOTRBO radios that is usually associated with analogue operation.

CT

In ETSI TS 102 361-1, Channel Timing (CT) is essential for synchronizing transmissions in TDMA direct mode operations. It establishes the timing boundaries for timeslot 1 and timeslot 2, which is crucial for the performance of TDMA systems that rely on precisely timed bursts. This synchronization information is conveyed through Channel Timing CSBKs (CT_CSBKs), which propagate slot timing details to all TDMA direct mode Mobile Stations (MS units). An MS evaluates the received CT_CSBK to determine if its sync pattern should set the channel slot timing.

CT_CSBK

See CT.

CTO

CTO stands for Channel Timing Opcode. It is a 2-bit information element used within the Digital Mobile Radio (DMR) standard, particularly in TDMA direct mode, to identify the purpose of a Channel Timing Control Signalling Block (CT_CSBK).

See CT.

C_ACKD

C_ACKD refers to an Acknowledgement PDU (Protocol Data Unit) transmitted by a Trunked Station Control Channel (TSCC). It is a type of positive acknowledgement that signals a message has been accepted or a request has been successfully processed.

C_ACKU

C_ACKU stands for Acknowledgement (inbound). It is a type of Control Signalling Block (CSBK) Protocol Data Unit (PDU) that is transmitted by a Mobile Station (MS). Its primary function is to serve as a positive acknowledgement from the MS to the Trunked Station Control Channel (TSCC) or a Trunked Station (TS), signalling that a message or request has been accepted or successfully processed by the MS.

C_AHOY

C_AHOY is a type of Ahoy Control Signalling Block (CSBK) Protocol Data Unit (PDU) that is transmitted by the Trunked Station (TS) or Trunked Station Control Channel (TSCC). Its primary purpose is to demand a response from a Mobile Station (MS) or to initiate various procedures with the MS on a DMR Tier 3 system.

C_ALOHA

C_ALOHA (or simply Aloha) is a type of Control Signalling Block (CSBK) Protocol Data Unit (PDU) that is transmitted by the Trunked Station (TS) or Trunked Station Control Channel (TSCC). Its fundamental role in a Digital Mobile Radio (DMR) Tier III system is to manage and control random access by Mobile Stations (MSs) on the outbound channel.

C_BCAST

A C_BCAST is a type of Control Signalling BlocK (CSBK) or Multi Block Control (MBC) Protocol Data Unit (PDU) that is transmitted on the Trunk Station Control Channel (TSCC) to provide system-wide announcements. These PDUs are generally intended for all Mobile Stations (MSs) listening to that TSCC. It can be used to announce or withdraw a TSCC; specify call timer parameters; transmit a Vote Now Advice; broadcast local time; broadcast Mass Registration (see MassReg); announce a logical/physical channel relationship; broadcast adjacent site information as well as general site Parameters or provide site timeslot synchronization.

C_SYS_Parms

A C_SYS_Parms is a Short Link Control (SLC) Protocol Data Unit (PDU) transmitted on the Trunk Station Control Channel (TSCC) in DMR Tier 3 systems. Its primary purpose is to broadcast system-wide parameters to all radios listening on that control channel (TSCC).

C_SYS_Parms PDUs are continuously or periodically transmitted on the Common Announcement Channel (CACH). The CACH is common to both logical channels (timeslots) on a physical channel. The entire Short LC payload, including C_SYS_Parms, can be delivered in four CACH bursts, meaning one SLC can be sent every 120 milliseconds. It is broadcast when at least one timeslot of the physical channel is configured as a TSCC, including scenarios where one timeslot is a TSCC and the other is a payload channel. It is never transmitted if neither timeslot is a TSCC.

The C_SYS_Parms PDU carries a subset of the System Identity Code (C_SYScode), along with the Reg information element and a Common_Slot_Counter. The specific elements are:

• A Short LC Opcode (SLCO) set to $0010_{2}$ for C_SYS_Parms.
• A 2-bit field indicating the network model (Tiny, Small, Large, or Huge).
• A 12-bit field for network and site definition, identifying a particular DMR trunked network.
• While part of the System Identity Code, the full 16-bit C_SYScode includes SITE, but only the most significant 14 bits of the C_SYScode (which include MODEL and NET) are carried in the CACH because the CACH is common to both logical channels.
• A 1-bit flag that specifies whether the system requires MSs to register before becoming active. $0_{2}$ means no registration is required, while $1_{2}$ means registration is required. This information element is also found in the C_ALOHA CSBK PDU.
• A 9-bit positive integer ranging from 0 to 511. This Common_Slot_Counter is incremented in each successive C_SYS_Parms Short Link Control PDU, rolling over to 0 after 511. It increments every 120 milliseconds.

Radios examine the C_SYScode information elements from TSCC PDUs, including those in C_SYS_Parms, to determine if they are authorized to acquire and become active on a TSCC.

If a radio is searching for a control channel, it can disregard a sampled channel by decoding the CACH and checking if there is no match in the C_SYScode subset thus eliminating the need to search for a CSBK containing the full C_SYScode. In a composite control channel scenario, where a TSCC may temporarily revert to a payload channel, the TSCC will cease transmitting C_SYS_Parms SLC and instead transmit P_SYS_Parms SLC to inform radios that its function has reverted to payload mode.

C_DGNAHD

The C_DGNAHD is a Unified Data Transport (UDT) outbound Header Protocol Data Unit (PDU) specifically used for the Dynamic Group Numbering Assignment (DGNA) service in DMR Tier 3 systems. Its primary function is to transfer dynamic talkgroups from the Trunk Station Control Channel (TSCC) to a called radio. This transfer occurs in the outbound phase of a DGNA procedure, following a successful inbound phase where the calling party uploads the DGNA data.

C_DGNAHU

A C_DGNAHU is a Unified Data Transport (UDT) inbound Header Protocol Data Unit (PDU). Its primary function is to transfer dynamic talkgroup information from a radio to the Trunk Station Control Channel (TSCC). This transfer occurs during the inbound phase of the Dynamic Group Numbering Assignment (DGNA) service.

C_MOVE

A C_MOVE is a Control Signalling BlocK (CSBK) Protocol Data Unit (PDU), which can also be transmitted as a Multi Block Control (MBC) PDU, used in DMR Tier 3 systems. Its primary function is to command radios) to move to an alternative Trunk Station Control Channel (TSCC).

C_NACKD

The C_NACKD is a Negative Acknowledgement Control Signalling BlocK (CSBK) Protocol Data Unit (PDU). It is transmitted outbound from the Trunk Station Control Channel (TSCC) or Trunk Station (TS) to a radio. Its primary function is to indicate that a service request or transaction initiated by an MS has failed or been rejected by the network.

C_NACKU

The C_NACKU is a Negative Acknowledge Response Control Signalling BlocK (CSBK) Protocol Data Unit (PDU).

The primary purpose of a C_NACKU is to serve as a response to PDUs (Protocol Data Units) from the TSCC or TS that demand a response. It signifies that a service request, an authentication challenge, a stun/revive command, or another transaction initiated by the network has failed or been rejected by the Mobile Station (MS). When an MS sends a C_NACKU due to a failed service request, the calling MS will typically abandon the associated service request and return to an idle state. Upon receiving a C_NACKU from a called MS, the TSCC typically sends an appropriate call failed response.

C_QACKD

The C_QACKD is a Queued Acknowledge Response Control Signalling BlocK (CSBK) Protocol Data Unit (PDU). It is transmitted outbound from the Trunk Station Control Channel (TSCC) or Trunk Station (TS) to a Mobile Station (MS).

C_RAND

The C_RAND is a Random Access Request Control Signalling BlocK (CSBK) Protocol Data Unit (PDU). It is primarily transmitted inbound from a Mobile Station (MS) to the Trunk Station Control Channel (TSCC) or Trunk Station (TS). C_RAND plays a crucial role in initiating various services and managing channel access within a DMR Tier 3 system.

C_SYScode

The C_SYScode, or System Identity Code, is a 16-bit information element in the signalling used on a DMR Tier 3 system that serves as a unique identifier for the network and radio site.

The C_SYScode identifies the DMR Tier 3 network and its sites. Radios use this to determine if they are authorized to access a particular control channel (referred to as a Trunk Station Control Channel TSCC). A radio must establish that the control channel is identified as one it is permitted to access. At sites with multiple control channels, the C_SYScode's PAR sub-field can help sub-divide the radio population for load sharing.

It is frequently transmitted via the control channel and carried within Control Signalling Block (CSBK) signalling packets. It is also embedded in the Common Announcement Channel (CACH) via the C_SYS_Parms Short Link Control PDU. While the full C_SYScode is 16 bits, only the most significant 14 bits are carried in the CACH, as the CACH is common to both logical channels and the PAR (partitioning) sub-field cannot be specified there. If a radio is searching for a control channel and trying to determine if access is allowed, it can use the CACH instead, thus avoiding the need to look for a CSBK containing the full C_SYScode. It is also present in C_ALOHA PDUs and C_BCAST PDUs.

The C_SYScode information element is composed of four key parameters:

Field	Name*	Number of bits	Values / Range [Min.,Max,]
MODEL	Network Model	2 bits	002 Tiny 012 Small 102 Large 112 Huge
NET	Network ID	9 if Model is Tiny 7 if Model is small 4 if Model is Large 2 if Model is Huge	[0,511] if the Model is Tiny [0,127] if the Model is small [0,15] if the Model is Large [0,3] if the Model is Huge
SITE	Site ID	3 if Model is Tiny 5 if Model is small 8 if Model is Large 10 if Model is Huge	[0,7] or up to 8 sites if the Model is Tiny [0,31] or up 32 sites if the Model is Small [0,255] or up to 256 sites if the Model is Large [0,1023] or up to 1024 sites if Model is Huge
PAR	Control Category	2 bits	002 Reserved 012 A 102 B 112 Both A and B

C_Syscode for a Tiny MODEL
Bit	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1
Field	0	0	N	N	N	N	N	N	N	N	N	S	S	S	P	P

C_Syscode for a Small MODEL
Bit	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1
Field	0	1	N	N	N	N	N	N	N	S	S	S	S	S	P	P

C_Syscode for a Large MODEL
Bit	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1
Field	1	0	N	N	N	N	S	S	S	S	S	S	S	S	P	P

C_Syscode for a Huge MODEL
Bit	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1
Field	1	1	N	N	S	S	S	S	S	S	S	S	S	S	P	P

While not explicitly part of the 16-bit C_SYScode structure, radio will also use a DMRLA value which is related to the above. This specifies the width (length in bits) of the SYS_AREA information field (or Location Area in Capacity Max). The SYS_AREA is formed by masking the most significant bits (i.e. starting from the left) of the SITE parameter with the DMRLA value. For example, a site with a C_SYScode of 840516 can have a DMRLA of anywhere between 1 and 8. If DMRLA was set to 1, the radio would only consider bit 10 of the C_SYScode. If DMRLA was set to 2 then the radio would consider bits 10 and 9. Since the SITE value in 840516 is 110, in order for this radio to attempt to register at this site, DMRLA would need to be set to 8 (so as to consider bits 10 to 3 of the C_SYScode).

When a radio attempts to acquire a control channel, it compares the transmitted MODEL; NET and SITE with that in its codeplug and, if there is no match, the radio is not authorized and will not attempt to register. If however these do match, the radio examines the PAR sub-field in conjunction with its own assigned Control Category (A or B) and if the radio is not permitted by the PAR value, the radio will not register.

If the C_SYScode is verified, the radio checks the SYS_AREA (derived from the SITE parameter) against a list of denied registrations. If it matches an entry in this list, the radio is not authorized to acquire that control channel. This denied list is discarded when the radio is switched off and on again.

If all checks pass, the radio is authorized and proceeds to monitor signal quality.

A radio is generally prohibited from transmitting any random access PDUs on a control channel until it holds a successful registration record for the verified SYS_AREA (unless registration is not required REG = 0).

During registration, the radio sends a C_RAND (Random Access Request) PDU that includes the C_SYScode within its REG_ADDR information element. The site controller or system will discard a C_RAND registration message if the C_SYScode does not match the system/site's C_SYScode. Possible responses from the TSCC to a registration request include: C_ACKD or C_NACKD (with Reason = Reg_Refused or Reg_Denied).

If registration was denied, the radio adds the SYS_AREA code to its list of denied registrations and re-enters control channel acquisition procedures, preventing further attempts on that channel for a period.

C_UDTHD

The C_UDTHD, or Unified Data Transport Outbound Header, is a type of multi-block Unified Data Transport (UDT) PDU. It is a component in the signalling used on a DMR Tier 3 system for transporting various types of data including system and user data, often requiring a response from the receiving MS or talkgroup.

C_UDTHU

The C_UDTHU, or Unified Data Transport Inbound Channel Header, is a Protocol Data Unit (PDU) used in DMR Tier 3 systems, specifically designed for inbound data transmission from a radio to a Trunk Station Control Channel (TSCC).

C_USBDD

The C_USBDD, or Unified Single Block Data: Control/Data, is a specific type of Protocol Data Unit (PDU) utilized in DMR Tier 3 systems. It functions primarily as a Poll Request PDU within the Unified Single Block Data (USBD) Polling Service.

Its core purpose is to poll inbound Unified Single Block Data from a Mobile Station (MS). It enables the Trunk Station Control Channel (TSCC) or Trunk Station Control Channel Alternate Slot (TSCCAS) to request data from an MS. As a Poll Request PDU, it is capable of sending up to 48 bits of data to the polled MS.

The USBD Polling Service, which uses C_USBDD, supports a subset of the Location Information Protocol (LIP). In this context, C_USBDD acts as a compressed LIP Immediate Location Update Request for highly efficient location updates.

CSV

CSV stands for Comma Separated Value.

MOTOTRBO CPS and RM support importing and exporting of CSV files to support easy manipulation of the following:

• Contact List
• Capacity Max Subscriber Access Control (SAC)
• Talkgroup Site Association

Although not part of CPS or RM, the System Advisor Alarms and Events can be exported to a CSV file for future analysis.

CWID

CWID (Continuous Wave Identification), also known as Base Station ID (BSI) is a MOTOTRBO repeater feature that can be used to identify the licensee operating a repeater or base station using analogue FM and Morse Code. This identification is often necessary to comply with the requirements of local radio regulatory authorities, such as the FCC in the USA.

For more information, see CWID.

D

D_Sync

D_Sync (general Data burst Sync) is a synchronization pattern used in DMR signalling.

Frame synchronization is the initial and fundamental step for a receiver to detect and process any message. Without it, embedded fields within the transmission cannot be extracted or interpreted. DMR employs different SYNC patterns to allow receivers to differentiate between voice bursts and data/control bursts. This distinction is critical for the proper decoding of the transmission.

D_Sync also helps differentiate between inbound and outbound channels, and between repeater channels and TDMA direct mode time slots.

When a radio receives a particular SYNC pattern, it can achieve bit synchronization and determine the centre of the burst. Once synchronized, it uses pattern matching to continuously verify the channel's presence and identify the burst's content.

DBSN

DBSN (Data Block Serial Number) is a 7-bit information element used to identify the serial number for a data block within a packet. This is needed to manage the order and retransmission of data blocks in packet data operations.

For the first attempt of transmission, these serial numbers start at 0 and increment up to $M-1$, where $M$ represents the value of the Blocks to Follow information element in the Header Block. In cases of subsequent retries, where not all blocks are typically included, these serial numbers enable the transmitter to indicate precisely which blocks are being sent.

DBSN is found as an information element in various Protocol Data Units (PDUs) related to data transmission, such as the R_1_2_LDATA PDU content for confirmed data.

DCDM

DCDM stands for Dual Capacity Direct Mode and is also referred to as TDMA direct mode. It is a digital feature that allows radios to support two-timeslot operation on a simplex channel without requiring repeaters.

DD

DD (Defined Data) is a 6-bit information element, found in the Short Data Header block, that specifies the data format for transmissions. It is used for the transmission of a small quantity of data among DMR entities.

The values for the DD information element indicate various predefined data formats, including:

• Binary
• BCD (Binary Coded Decimal)
• 7-bit character
• 8-bit ISO/IEC 8859-1
• 8-bit ISO/IEC 8859-2

The DD information element is part of the DD_HEAD PDU (Defined Data short data packet Header). This PDU is specifically used for Defined Data short data delivery. Defined data can be transmitted using various coding rates, such as rate ½, ¾, or 1 coded data. It can also be sent as either confirmed or unconfirmed data. The DD_HEAD PDU also helps in indicating the type of response (e.g., ACK or NACK) required for a data transmission.

DD_HEAD

See DD.

DDMS

DDMS (Device Discovery and Mobility Service) is a Motorola Solutions application that runs on Microsoft Windows which is used to manage radio presence and mobility notifications. It would only be used when the radios must interact with a software application and that application needs to know whether a radio is active (turned on) and where (which site and timeslot) it is located. The radio sends its presence information to DDMS using ARS.

DDMS would not be used on MOTOTRBO Capacity Max systems.

DGNA

DGNA (Dynamic Group Numbering Assignment) is a service in DMR Tier 3 systems that allows for the dynamic management of talkgroup identities assigned to radios. It gives the system operator the ability to dynamically add or remove talkgroup addresses on a radio. When a radio receives a DGNA command to add a talkgroup, it can replace the contact and alias of the current personality with the newly assigned DGNA talkgroup.

DGNAI

DGNAI is an address used to identify the Dynamic Group Number Assignment. For more information see DGNA.

DHCP

DHCP (Dynamic Host Configuration Protocol) is a network protocol used to automatically assign IP addresses and other network configuration parameters to devices connected to a network. This automation simplifies network management by eliminating the need for manual static IP address configuration.

DI

DI (Dynamic Identifier) is an information element used for managing timing and leadership among radios on a direct mode (simplex) channel. It consists of 2 bits, that indicate the Leader Preference, and is part of the Wide Area Timing Identifier (WATID).

DISCON

DISCON is a mnemonic for a Maintenance PDU that signifies a "Disconnect" command, indicating the end of payload channel use. It is used to signify the termination of a call or the end of a payload channel's

The radio (MS) that initiated a talkgroup call or is engaged in an individual call, can signify the end of the call by transmitting a number of P_MAINT (Maintenance) PDUs with the Maint_Kind (Maintenance Kind) set to DISCON. When a radio is the recipient of a talkgroup call, it ends its call without sending any PDUs, and the system detects the end of the call through other means, such as the expiration of data hangtime or transmission of an unconfirmed data message. The Trunked Base Station can also detect that a packet call has ended and then sends P_CLEAR PDUs.

When a radio transmits P_MAINT (Maint_Kind = DISCON), it sends these PDUs consecutively and then returns to the control channel acquisition procedures. It is suggested that the TSCC (Trunk Station Control Channel) sampled is the one that transferred the call to the payload channel. The Trunked Base Station response to an applicable P_MAINT (Maint_Kind = DISCON) is a P_CLEAR PDU.

DISPATI

DISPATI is an address that identifies the system dispatcher. It functions as a gateway address within a DMR Tier 3 system, primarily used for extended addressing in multi-part call setups and various data transfer services. It acts as a gateway identifier, especially for services routed to a dispatcher. For calls to these destinations, the dialled destination needs to be passed to the system, and the Unified Data Transport (UDT) mechanism provides an unambiguous transfer.

DISPATI is used when extended addressing is required, where the destination is not a direct radio address but a line-connected terminal device, such as a dispatcher. It is associated with payload aligned timing. Note that there is also DISPATDI, which is a gateway address for the system dispatcher using payload offset timing.

DISPATI is involved in data transfer services, when data transfer service is required for extended addressing, DISPATI is one of the identifiers used. It is also involved in (UD) Short Data Message Services in that it instructs the calling party to send its extended address using the UDT mechanism. For a dispatcher destination in this service, the calling party uplinks BCD dialled digits.

It is also a gateway identifier for call diversion. For a dispatcher destination, the calling party sends BCD dialled digits.

DISPATI can also be a target for a status call.

In multi-part call setups, a random access PDU (Protocol Data Unit) may set the destination address to DISPATI to indicate a call service to the system dispatcher. The system would then respond with an AHOY PDU to request the necessary information, such as dialled digits, using the UDT mechanism.

DLL

DLL stands for Data Link Layer and is the second layer in the DMR Air Interface Protocol Stack. It operates above the Physical Layer (Layer 1) and interacts with the Call Control Layer (Layer 3). Its primary function is to handle the sharing of the medium by a number of users. It also conceals the physical medium from the layers above it.

The DLL is vertically divided into two parts:

1. User plane (U-plane) which transports information without addressing capabilities, such as user voice services or voice payload.
2. Control plane (C-plane) which contains signalling information, including both control and data, with addressing capabilities.

This vertical division allows for the separation of functionality, though further sub-division into Medium Access Control (MAC) and Logical Link Control (LLC) is often performed in radio air interface protocols but is not very well defined.

The main functions of the Data Link Layer (Layer 2) include:

• Channel coding (Forward Error Correction - FEC, Cyclic Redundancy Checksum - CRC).
• Interleaving, de-interleaving, and bit ordering.
• Acknowledgement and retry mechanisms.
• Media access control and channel management.
• Framing, superframe building, and synchronization.
• Burst and parameter definition.
• Link addressing (source and/or destination).
• Interfacing of voice applications (vocoder data) with the Physical Layer (PL).
• Data bearer services.
• Exchanging signalling and/or user data with the Call Control Layer (CCL).

The DLL supports both unconfirmed and confirmed data transmission services, which are the basis for higher-layer bearer services like Internet Protocol (IP) and Short Data. It is described in ETSI TS 102 361-1 §5.

Also see AI.

DMR

See MOTOTRBO.

DMRLA

DMR Location Area is an information element in the C_SYScode transmitted on the control channel (TSCC) of a DMR Tier 3 trunked systems.

The information required for radios to identify a DMR Tier 3 network is contained within the System Identity Code. This is regularly transmitted within the CACH of control channels at each RF site. ETSI TS 102 361-4 defines a 16-bit System Identity Code (C_SYScode) that is made up of the following subfields.

Bit	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1
Function	M	M	X	X	X	X	X	X	X	X	X	X	X	X	P	P

DMR Tier 3 networks may range from small systems consisting of maybe one or two RF sites; to nationwide systems with hundreds of RF sites.  To provide flexibility and the coexistence of many systems in the same frequency band, ETSI TS 102 361-4 defines a means for the System Identity Code to be split into four possible network models (M). The network model sets the value of bit 16 and 16 of the C_SYScode as follows.

Network Model	Bit 16-15 of C_Syscode	Number of bits for NET	Number of bits for SITE
Tiny	00	9	3
Small	01	7	5
Large	10	4	8
Huge	11	2	10

As can be seen in the above table, the Network Model selection determines how many bits are allocated to the NET and SITE subfields.

As an example, if a Small network model is chosen (bit 16 is 0 and bit 15 is 1) then bits 8-14 are reserved for the NET (N in the below table) subfield and bits 3-7 are available for the SITE subfield (S in the below table). The value in the NET subfield is the System ID and is the (decimal) number one would enter into MOTOTRBO Radio Management together with the Network Model selection.

Bit	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1
Value	0	1	N	N	N	N	N	N	N	S	S	S	S	S	P	P

The SITE subfield contains the Site ID. In a DMR Tier 3 system, each RF site will have a unique Site ID. This is the Site ID which is set up in the table located in the Site Selection set (used by the radios) within MOTOTRBO Radio Management.

The RF sites in a DMR Tier 3 system can be organised into multiple areas. An area can therefore consist of one or more RF sites. The primary function of DMRLA is to facilitate location management for radios across a wide area network. In theory, by knowing which area a radio is located in, the system avoids searching the entire network to find a specific radio. This, in principle, significantly reduces call setup time and control channel loading.

The Length of Area (DMRLA) refers to the number of bits in SITE the radio will need to consider. So if the Length of Area in the configuration software is set to 3; and the network model is Small, then the radio will only consider bits 7 - 5 of the SITE subfield. Similarly, if the Small network model is chosen, then the Length of Area cannot be more than 5. The minimum is however 1 though some vendors will allow this to be set to 0. If set to zero the radio will consider sites where the System ID is a match (i.e. SITE will be ignored).

The DMRLA can also be used to control which RF sites a particular radio (or certain radios) may access. Depending on the vendor, this value might be shown as Length of Area in their configuration software. Capacity Max does not use Length of Area so the (full) SITE subfield must be used as the Site Number in the Site Selection set. From a system planning point of view, it is preferable to allow a radio to roam to all sites and restrict site access at a system level (rather than in each radio configuration). This allows granular site-access changes to be made without ever having to change something in the radio.

Bits 1 and 2 of C_SYScode are allocated to the PAR (Partition) subfield (P in the above table). Some vendors will call this the Control Category. In Radio Management you will find this setting in the Site Selection set: Partition Category. Practically, there are only two choices: A and B. Some vendors will have an option to allow A and B. If a radio is set up to register on sites with a control channel set to PAR=A and it finds a site which has PAR=A and B then it will consider this site.  However, if the radio is set finds a site which has PAR=B then it will ignore this site. The idea behind PAR is to allow a site to have two control channels. This would allow the number of radios to be divided between the two control channels. Capacity Max does not need to use this as - in Advantage Mode - timeslot 2 of the control channel host repeater can be used to efficiently handle mass registration.

Before attempting to register on the site, the radio will evaluate the System Identity Code. It will also evaluate the control channel (as well as any control channels on neighbouring sites) for signal strength and bit error rate.

DMO

Direct Mode Operation or Direct Mode is a mode of operation where radios can communicate with each other outside the control of a network. This means thatradios can communicate without the need for any additional infrastructure equipment, such as a repeater.

Direct mode supports one transmission per 12.5 kHz frequency, resulting in 12.5 kHz equivalent (12.5e) spectral efficiency. • Channel Access: In direct mode, a DMR entity (MS) monitors the Received Signal Strength Indication (RSSI) level to determine if activity is present on a channel before transmitting. If no activity is detected after a certain period, it assumes the channel is idle. If activity is present, it attempts to synchronize to determine if it's DMR activity or non-DMR activity.

In TDMA direct mode, to minimize inter-timeslot interference, all radios in a wide area system are expected to transmit with the same channel slot timing. One radio is therefore appointed as the wide area timing leader to set this timing, and this timing information is shared across radios.

TDMA direct mode channel access is designed to use three types of ETSI DMR channel access settings: Impolite, Polite to own Colour Code, and Polite to All. A radio operating in TDMA direct mode is programmed to operate on either Slot 1 or Slot 2, and channel access can be initiated from various radio high-level states.

ETSI TS 102 361-1 Annex F and ETSI TS 102 361-2 Annex F list various timers and constants relevant to DMR operations, which would include direct mode, such as T_ChMonTo (channel activity monitoring time-out).

DNF

When IP data is sent across a DMR network, the DNF bit can be set in the IP header of a datagram. When an IP message received by a Mobile Station exceeds the Maximum Transfer Unit (MTU) for the accessory interface and this DNF bit is set, it indicates that fragmentation is needed but is prohibited by the sender. This condition can lead to an ICMP (Internet Control Message Protocol) error message being generated, specifically "Fragmentation needed and DNF set", to report the issue.

DNS

The Domain Name System (DNS) is a hierarchical and distributed name service that provides a naming system for computers, services, and other resources on the Internet or other Internet Protocol (IP) networks. It associates various information with domain names (identification strings) assigned to each of the associated entities. Most prominently, it translates readily memorized domain names to the numerical IP addresses needed for locating and identifying computer services and devices with the underlying network protocols. The Domain Name System has been an essential component of the functionality of the Internet since 1985.

For example, this site is hosted at https://107.161.23.71. For most, this string would be impossible to remember but https://cwh050.mywikis.wikiis something easier to remember. It also allows redundancy since the same website can be hosted on a backup server and used if the main server goes down for whatever reason.

DP

DP stands for Destination Port and is identified as an information element within the Layer 2 Protocol Data Unit (PDU) description.

• UDP Header: A visual representation of a UDP Header clearly includes a "Destination Port" field

DPF

DPF stands for Data Packet Format. It is an information element used for data packet identification and is found within the header blocks of various Packet Data Units (PDUs). The DPF field in the header block is specifically used to distinguish between confirmed and unconfirmed packets. This means it indicates whether the recipient of a packet is required to send an acknowledgment of receipt (confirmed) or not (unconfirmed).

Examples of Values:

• For an Unconfirmed data packet Header (U_HEAD) PDU, the DPF value is 0010₂.
• For a Proprietary Header (P_HEAD) PDU, the DPF value is 1111₂.
• For a Defined Data Header (DD_HEAD) PDU, the DPF value is 1101₂.

DPID

DPID (UDP Destination Port IDentifier) is an index to a predetermined Destination IP Address. The DPID value can indicate whether the UDP Destination Port Number is in an optional Extended Header.

DPL

DPL (Digital Private Line) - also known as DCS (Digital-Coded Squelch) or CDCSS (Continuous Digital-Coded Squelch System) - is an analogue signalling format designed as the digital replacement for PL (CTCSS). In the same way that a single CTCSS tone would be used on an entire group of radios, the same DCS code is used in a group of radios.

DCS adds a 134.4 bit/s (sub-audible) bitstream to the transmitted analogue audio. The code word is a 23-bit Golay code which has the ability to detect and correct errors of 3 or fewer bits. The word consists of 12 data bits followed by 11 check bits. The last 3 data bits are a fixed '001', this leaves 9 code bits (512 possibilities) which are conventionally represented as a 3-digit octal number. Note that the first bit transmitted is the LSB, so the code is "backwards" from the transmitted bit order. Only 83 of the 512 possible codes are available, to prevent falsing due to alignment collisions.

DT

DT stands for Terminator Data and is used in conjunction with data formatting and link control within Digital Mobile Radio (DMR) systems.

DTMF

Dual-tone multi-frequency (DTMF) signaling is a telecommunication signaling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centers. DTMF was first developed in the Bell System in the United States and became known under the trademark Touch-Tone for use in push-button telephones, starting in 1963. The DTMF frequencies are standardized in ITU-T Recommendation Q.23.

Also see DTMF.

E

ECA

Enhanced Channel Access (ECA) is a Motorola Solutions proprietary feature that improves the reliability of transmissions by minimizing over the air collisions when two or more radios attempt to initiate a call simultaneously.

It is a channel access procedure where a call-initiating radio transmits a channel access request and then listens on the channel to determine the request's status. The radio proceeds with the call transmission only after it obtains access to the channel. ECA provides the ability to reserve a channel for one of the call-initiating radios, granting exclusive access for a short duration.

See Enhanced Channel Access.

ECDSA

ECDSA (Elliptic Curve Digital Signature Algorithm) is a public key algorithm used in security and certificate management. Specifically, i is a type of algorithm for generating key pairs in a Public Key Infrastructure (PKI) system and would be used with MOTOTRBO radios which support Wi-Fi.

See Elliptic Curve Digital Signature Algorithm

EDEG

EDEG is an information element that has a length of 8 bits. It is part of the Appended Data Long NMEA Format Unspecified. This format is used with Unified Data Transport (UDT) NMEA format to send location data.

EGPS

Enhanced GPS, or more broadly, Enhanced GNSS (Global Navigation Satellite System) is an enhancement of the GPS Revert Channel functionality that supports higher throughput and increased reliability for location updates. It specifically aims to reduce over the air collisions among radios sending location data, that normally occurs when standard GPS Revert Channel is used due to desynchronized access. It ensures effective and efficient channel use by ensuring radios access the channel in a synchronized manner.

See Enhanced GPS.

EID

An Entitlement ID is a random 16 character string generated by Motorola Solutions and sent via email to a customer when a software feature has been ordered. Using the EID, a technician will register and activate a feature licence via the CPS or RM.

Also see CfS license.

EMB

Embedded signalling (EMB) is a type of a Protocol Data Unit (PDU) that is used for embedded signalling within a burst. The EMB PDU facilitates embedded signalling within a burst. This embedded signalling can include Link Control (LC), Reverse Channel (RC) information, information related to Privacy (encryption), or a Null embedded message. LC messages, in particular, are carried in the embedded field of voice bursts to facilitate late entry.

The EMB PDU has a length of 16 bits. It contains several information elements such as the Colour Code (CC) (4 bits); Pre-emption and power control Indicator (PI) (1 bit); Link Control Start/Stop (LCSS) (2 bits) and EMB parity (9 bits). The EMB PDU is placed within a burst. For an embedded outbound Reverse Channel (RC) burst, RC signalling is placed in a single embedded 48-bit EMB/LC field. The 9-bit EMB parity utilizes the Quadratic Residue (16,7,6) FEC (Forward Error Correction). The embedded signalling is also protected using a Block Product Turbo Code (BPTC), which consists of Hamming (16,11,4) row codes and simple parity checks for the column codes.

During transmission, the bits of the encoded embedded signalling are interleaved. Each row of the resulting Transmit Matrix, which is 32 bits long, is placed into the embedded signalling field of sequential bursts. The LCSS bits within the EMB field are used to frame the beginning, continuation, and end of a complete LC message

EMERG

In DMR systems, EMERG refers to an information element that indicates whether a service request is an emergency. It consists of 1 bit where 02 signifies a non-emergency and 12 signifies an emergency service. It is part of the Service_Options information element found in C_RAND (Random Access Request) PDUs for various call types, including voice and packet data services.

Emergency calls take precedence over all other calls. An emergency call may be pre-emptive, meaning it can cause another ongoing call to be cleared down if the necessary resources are not immediately available. This is facilitated by Emergency Pre-emption MS De-key, which allows a new emergency call to utilize a payload channel. The system uses a Reverse Channel (RC Command = 0100₂) to instruct the transmitting radio to cease transmission.

If EMERG is set to 12 (emergency service), the PRIORTY_SV (Priority level) information element is automatically set to 002, which corresponds to "Normal (low) priority". This implies that the EMERG=12 flag itself grants the highest priority and pre-emptive capabilities, overriding explicit priority settings in the PRIORTY_SV field. Priority 3 (112) is generally considered the highest explicit priority level. For emergency random access requests, a specific maximum number of retries, NRand_NE, is used, which differs from the NRand_NR used for non-emergency requests. SDL (Specification and Description Language) diagrams illustrate these emergency random access procedures.

Specific timers are defined for emergency calls, such as T_EMERG_TIMER.

On DMR Tier 3 systems, users can initiate an emergency priority call by dialling the call modifier string #9*nn#. There are also specific dialled strings for "Emergency All Call," such as *1962, *1972, and *1982, associated with different DMR IDs for site-specific or system-wide emergency calls.

If the Trunked System Control Channel (TSCC) transmits a Channel Grant PDU with the Emergency bit (EMERG) set to 12 to an individual MS or talkgroup, the MS may abandon its current call and immediately switch to the specified payload channel. An emergency ALS request can be made by setting EMERG to 12 in the C_RAND PDU when requesting an ALS voice service. The ALS service also has specific timers for emergency calls, such as T_ALS_E.

Also see Emergency.

EMINF

In DMR systems, EMINF is an abbreviation for Longitude Fractions of minutes. It is an information element used in conjunction with EDEG, which represents Longitude Degrees. Both are part of location information within DMR protocols.

EN_PTT

EN_PTT is a value associated with the Protect_Kind information element within Digital Mobile Radio (DMR) systems. It plays a role in controlling PTT functionality in radios

A DMR Tier 3 system can send P_PROTECT PDUs with the Protect_Kind set to EN_PTT. These P_PROTECT PDUs can be addressed to an individual radio; a talkgroup, or to ALLMSID to enable their PTT. Since P_PROTECT PDUs are unacknowledged, they may be repeated at Layer 2 to ensure delivery.

When a radio receives a P_PROTECT PDU with Protect_Kind set to EN_PTT addressed to its individual address, its talkgroup address (previously transmitted in the Channel Grant PDU), or ALLMSID, the radio will re-enable its PTT, unless it was the recipient of a broadcast call.

A related value, EN_PTT_ONE_MS enables PTT for the radio matching the target address while disabling PTT for all other radios. In this case, if the (DMR Tier 3) system transmits P_PROTECT (Protect_Kind = EN_PTT_ONE_MS) PDUs addressed to an individual radio ID, that radio will enable its PTT and would be allowed to transmit as soon as the payload channel is free. During this period, PTT functionality will be disabled on all other radios. The system may use P_PROTECT (Protect_Kind = EN_PTT_ONE_MS) PDUs to prevent an interrupted Ambient Listening Service (ALS) radio from automatically retransmitting after a transmit interrupt request on the outbound channel.

Enc_Dibit

In DMR systems, Enc_Dibit refers to the output Dibit from a trellis encoder. A Dibit itself is defined as 2 bits grouped together to represent a 4-level symbol.

EOC

In ETSI TS 102 361, EOC stands for End Of Call. This term is used to signify the conclusion of a call. For a group call, the End Of Call (EOC) occurs when the call hangtime expires. Similarly, for an individual call, the End Of Call (EOC) also occurs at the expiration of call hangtime. Call hangtime is a period used to extend a call beyond the End Of Transmission (EOT).

EOR

In ETSI TS 102 361, EOR can refer to two different terms, depending on the context. End of Receive is an event that causes High Level Base Station transitions. When an EOR occurs, it will typically transition the repeater to the Call_Hangtime state.

The Data Link Layer (DLL) can send an EOR primitive to the Call Control Layer 1 (CCL_1) process. This action initiates the Call Hangtime Timer (T_CallHt) and moves the CCL_1 process into the Call_Hangtime state. Simultaneously, the DLL also sends an EOR_Slot_1 primitive to the CCL_BS process. If slot 2 is in the Channel_Hangtime or Call_Hangtime states, it transitions to the Hangtime state upon receiving an EOR_Slot_1 primitive. If slot 2 is in the Repeating_Slot state, the CCL_BS transitions to the Repeating_Slot_2 state.

EOT

In ETSi TS 102 361, EOT stands for End Of Transmission and signifies the conclusion of an active transmission.

For a group call, the EOT is accomplished by transmitting the entire last voice superframe (through voice burst "F") followed by a Terminator with LC Data Type burst containing the Group Voice Channel User (Grp_V_Ch_Usr) LC Message. Similarly, for an individual call, the EOT involves transmitting the entire last voice superframe (through voice burst F) and then sending the Unit to Unit Voice Channel User (UU_V_Ch_Usr) LC Message using a Terminator with LC Data Type burst. For an all call, the end of transmission is signaled by the source Mobile Station (MS) using a Grp_V_Ch_Usr PDU with a Terminator with LC data slot type after the last superframe (voice burst F). When the radio PTT button is released, the Data Link Layer (DLL) sends an EOTx primitive to the Call Control Layer (CCL). The radio then pads out the superframe and transmits a Terminator_with_LC PDU (e.g., Grp_V_Ch_Usr).

Call hangtime is a period that is utilized to extend a call beyond the EOT. This means a call might technically end its transmission (EOT) but remain active for a short "hangtime" before the actual End Of Call (EOC).

If a Transmit Time Out timer expires during a voice transmission, the radio stops transmitting either immediately or after the end of the current superframe plus one burst. If it expires during a data transmission, the MS stops transmitting immediately. If the overall voice payload call timer (e.g., T_ALS or T_ALS_E) expires, the radio transmits a Terminator with LC before sending P_MAINT PDUs to indicate the call's end. If the overall data packet payload call timer (T_PACKET_TIMER) expires, the MS transmits a Data Terminator with LC before sending P_MAINT PDUs.

If a radio fails to detect synchronization (SYNC) after dekeying (i.e., after EOT), it may transition to an "Out_of_Sync" state, indicating the end of the call.

In "transmission trunking" mode, a call is specifically terminated after the EOT of each PTT item.

ESU

Enhanced Software Update(r) (ESU) is a software application provided to upgrade the software of the Capacity Max System Server (CMSS). It is specifically used for maintenance tasks related to the CMSS. The ESU is used to upgrade the other CMSS components such as The Trunking Controller, Voice and Data Gateway, and System Advisor - all of which cannot be upgraded from within MOTOTRBO Radio Management.

ESU resides on the Capacity Max System Server (CMSS) as either a Virtual Machine or Container. It often assigned specific IP addresses within the CMSS Gateway Network subnet (default 172.21.0.3). It can share the Ethernet ports on the CMSS with other components like ESXi and System Advisor. The ESU Client software is accessed through a web browser on any personal computer that meets specific computer specifications.

ETSI

See European Telecommunications Standards Institute.

F

FEC

Forward error correction (FEC) is a digital signal processing technique that adds redundant data to a message before transmission to help the receiver detect and correct errors without having to request retransmission from the sender. This is especially useful for DMR since re-sending data is impractical.

At its core, FEC works by using an error-correcting code (ECC). When data is prepared for transmission, it's divided into blocks. The sender then uses an algorithm to generate extra bits, known as parity bits or redundant data, from the original data block.  These new bits, along with the original data, are sent together. The amount of redundancy added is determined by the specific code being used and the expected level of noise or interference on the communication channel. A higher amount of redundancy allows for more errors to be corrected but also reduces the overall data throughput.

When the receiver gets the data, it uses the same algorithm to check the relationship between the original data and the redundant bits. If any bits have been corrupted during transmission (e.g., a 0 flipped to a 1 or vice versa), the receiver can use the redundant information to identify and correct the error. This is a crucial distinction from simple error detection, which only tells the receiver that an error occurred, requiring a retransmission request.

In DMR, voice bursts carry vocoder frames that include FEC but for data and control messages, FEC (and CRC) is part of the payload. FEC encoding is often applied before interleaving to further enhance error resistance. According to ETSI TS 102 361, information bits are FEC encoded to form an "FEC encoded matrix," which is then typically interleaved before transmission. This process adds redundancy to the data, allowing errors to be detected and corrected at the receiver.

DMR uses the following FEC codes:

• Quadratic Residue (16,7,6) FEC: Used for EMB parity within the embedded signalling field.
• Golay (20,8) FEC: Used for Slot Type parity.
• Hamming (7,4) FEC: Used for CACH TACT bits.
• Variable Length Block Product Turbo Code (BPTC): Used for general embedded signalling. This includes Hamming (16,11,4) row codes and simple parity checks for column codes.
• Single Burst RC BPTC (Reverse Channel Single Burst BPTC): Used for Reverse Channel (RC) signalling.
• Non-RC Single Burst BPTC: Used for Single Burst embedded LC.
• Block Product Turbo Code (BPTC(196,96)): A frequently used code for various PDUs.

FID

FID stands for Feature set ID and is an information element used in DMR systems to identify one of several different so-called feature sets. The FID information element has a length of 8 bits.

There are three possible value ranges for FID, these are:

1. Standardized Feature Set ID (SFID) 000000002 designates the standardized feature set ID for services and facilities defined in ETSI TS 102 361-2. This is also referred to as the default feature set.
2. Manufacturer's Specific Feature Set ID (MFID) 000001002 or any value in the range 011111112 to 111111112 are reserved for manufacturer-specific feature set IDs. These allow manufacturers to define and implement private feature sets that might not be understood by products from other manufacturers or those not supporting that specific feature set. Multiple manufacturers or application designers may use the same MFID.
3. Reserved for Future Standardization: Values like 000000012, 000000102, and 000000112 are reserved for future standardization.

FID would be used with the following:

• Full Link Control (FULL LC) PDU. FID is an information element within the FULL LC PDU.
• Control Signalling Block (CSBK) PDU. FID is also used within the CSBK PDU.
• Terminator Data Link Control (TD_LC) PDU. In this PDU, the FID is specified to be the SFID (000000002)
• Talker Alias Header Info PDU: For this PDU, the FID is set to SFID (000000002)

When a radio receives feature signalling it doesn't support, and this signalling contains an SFID, the radio may respond with FNS (Feature Not Supported) signalling. Manufacturers may also validate the SFID as part of the Base Station activation process.

For packet data transmissions, the FID identifies one of several different feature sets and is typically carried in the second data header. If transmissions are not standardized, they are only available via an alternative MFID in the second data header. FID is present in Private Data Channel Grant PDUs (both single block CSBK and MBC header types), and is set to 000000002. Similar to private data channel grants, FID is present inTalkgroup Data Channel Grant PDUs and is set to 000000002

The C_ALOHA PDU, used in random access control; various C_AHOY PDUs, used for services like authentication challenges, stun/revive, and unsolicited radio checks, include the FID. The Random Access Request PDU; the Acknowledgment PDUs (C_ACKVIT PDU and C_ACKU PDU) all include a FID. In all cases, this set to 000000002 (SFID).

P_Clear PDU, used to clear a call from a payload channel; P_Protect PDU, used for channel protection and P_MAINT PDU, maintenance PDU all contains the FID. In all cases, this set to 000000002 (SFID).

The FID, in conjunction with the Full Link Control Opcode (FLCO), is needed to ensure layer 2 interoperability. Standardized features must be accessible only via the combination of the default SFID and its corresponding FLCO. Non-standardized features are available only through an alternative MFID.

ETSI is the central body responsible for the management of Manufacturer's Feature set ID (MFID) values.

FIFO

FIFO stands for First In First Out. It describes a storage type where information is retrieved in the exact order in which it was stored.

FIN

In DMR Tier 3 systems, FIN stands for Fleet Individual Number. It is part of the radio ID when the MPT1343 numbering scheme is used in which case, the ID is made up of:

• NP (Number Prefix): 3 digits
• FIN (Fleet Individual Number): 2 digits
• IN (Individual Number): 3 digits

The range of FIN is 20 to 89.

FLCO

Full Link Control Opcode (FLCO) is an information element used to identify an over-air facility (feature) within a specific facility set. It is a core element for ensuring feature interoperability at the air interface and is described in ETSI TS 102 361-2 and ETSI TS 102 361-3.

FLCO values are specified for various Link Control (LC) messages, including:

• Group Voice Channel User (Grp_V_Ch_Usr): FLCO 0000002. Used for transmission addressing in the Voice LC Header and indicating the End of Transmission (EOT) in the Terminator with LC.
• Unit to Unit Voice Channel User (UU_V_Ch_Usr): FLCO 0000112. Used for transmission addressing in the Voice LC Header and Terminator with LC for individual calls.
• Talker Alias header (Talker_Alias_hdr): FLCO 0001002. Used for in-band talker alias transmission.
• Talker Alias block 1, 2, and 3: FLCO values are 000101₂, 000110₂, and 000111₂, respectively.
• GPS (GNSS) Info: FLCO 0010002.
• Terminator Data Link Control (TD_LC): FLCO 1100002.

The FLCO works closely with the Feature set ID (FID) which identifies the feature set (e.g., standard or manufacturer-specific). The FLCO identifies the specific feature within that set.

For standard features defined in ETSI TS 102 361, accessibility is only permitted via the combination of the default Standardized Feature Set ID (SFID) and the corresponding FLCO. Non-standardized features are accessible only via an alternative Manufacturer's Feature set ID (MFID). The combination of FLCO and FID is contained within the 7 octets of data that comprise the Full LC.

FM

FM either refers to Factory Mutual or Frequency Modulation.

Factory Mutual

Factory Mutual, now officially known as FM Global, is an American mutual insurance company that specializes in providing property insurance and loss prevention services, primarily to large corporations worldwide. A key division of the company is FM Approvals, which is a third-party testing and certification service. The "FM Approved" mark on a product or service signifies that it has met the company's rigorous standards for quality, technical integrity, and performance, particularly for fire safety and property protection.

In the context of radio communications equipment, FM Approved refers to equipment either certified against FM3610 or FM3611. MOTOTRBO radios are instead certified by UL according to TIA4950 which provides the same level of intrinsic safety as FM3610.

Frequency Modulation

FM is defined Physical Layer specifications for ETSI TS 102 361. The standard mentions a FM Demodulator as part of the procedure for measuring peak positive and peak negative deviation of 4FSK modulation. MOTOTRBO radios use a custom SDR (Software Defined Radio) chipset for demodulation and conversion. The first generation MOTOTRBO radios used a DSP (Digital Signal processor) for this purpose.

FMF

FMF stands for Full Message Flag and is an information element used in the receiver to signal that the Pad Octet Count (POC) information element indicates the amount of data being transported in the complete packet. It is used in various data packet headers, including confirmed data headers and Unified Data Transport (UDT) headers. In ETSI TS 102 361, it is listed as an information element in the Confirmed packet Header (C_HEAD) PDU; Defined Data short data packet Header (DD_HEAD) PDU and is included in the Unified Data Transport Header (UDT_HEAD) PDU.

The FMF is a single bit where a value of 12 signifies the first try for the complete packet and 02 signifies subsequent tries.

For multi-fragment confirmed data messages, the most significant bit of the Fragment Sequence Number (FSN) field functions similarly, indicating the last fragment (1xxx2) or subsequent fragments (0xxx2). If Selective Automatic Repeat reQuest (SARQ) is not used for confirmed data, the FMF element in a response header PDU shall be set to 12 on the first transmission attempt and 02 on subsequent attempts.

On a DMR Tier 3 system and in the context of the UDT Header Outbound PDU, the Full Message Flag (FMF) is listed as an information element. The UDT mechanism allows the FMF element to be explicitly set.

FNS

The Feature Not Supported (FNS) signalling is used when a radio is individually addressed with feature signalling it does not support. The condition that triggers FNS is the reception of non-supported feature signalling via a Protocol Data Unit (PDU) that contains a Standard Feature set ID (SFID) and a Control Signalling Block Opcode (CSBKO) that the radio does not support. In this case, the target radio attempts to respond to the source radio with a Negative Acknowledgement Response (NACK_Rsp) CSBK PDU.

FOACSU

FOACSU is a call handling mechanism used in DMR Tier 3 trunking systems for individual voice and packet data calls, serving as an alternative to the Off Air Call Set-Up (OACSU) method. When FOACSU is used, the traffic channel is only assigned when the called party user has specifically answered the call. In contrast, with OACSU, the system determines when to assign the traffic channel, and the assignment may happen immediately after the call initiation, whether or not the called party answers.

The FOACSU process involves checks and confirmations before allocating payload channel resources:

1. The calling radio (A) initiates the call via a Service Request.
2. The Trunked System Control Channel (TSCC) sends an AHOY PDU addressed to the called radio (B). This AHOY PDU is specifically configured for FOACSU by setting the Service_Kind_Flag to 12. This PDU checks if radio B is ready to accept the call and starts the timer T_AnswerCall.
3. Radio B responds with an acknowledgement (ACK PDU) to the TSCC, and then alerts the user to the incoming call. If the radio is FOACSU enabled, a valid response to the AHOY (Service_Kind_Flag 12) is sent as a C_ACKU (Reason MS_ALERTING), meaning the radio is alerting but not yet Ready For Communication (RFC).
4. The TSCC sends a mirrored acknowledgement PDU back to radio A to indicate that radio B is ringing.
5. Only when the called party (radio B) explicitly chooses to accept the call by RFC (e.g. by pressing answer) does the system allocate a payload channel. The called party achieves this by sending a C_RAND - Call Answer Service request with the ACCEPT information element set to 02.
6. If the called party chooses to reject the call, they send a C_RAND - Answer Call Service request with ACCEPT set to 12.

The timer T_AnswerCall is defined as the timeout for the called MS after receiving an AHOY for FOACSU. This timer value can range from 2 seconds to 60 seconds.

FQDN

A FQDN (Fully Qualified Domain Name) is the complete and unambiguous internet address for a host or computer, ensuring its exact location within the Domain Name System (DNS). It consists of a hostname, domain name, and top-level domain (TLD), such as mail.example.com, which distinguishes it from a partial domain name. FQDNs are crucial for pinpointing network resources, authenticating email, and establishing precise security rules.

FRU

FRU refers to Field Replaceable Unit. The goal of the FRU concept is to maximize system uptime and aid the end user or maintainer in lowering their inventory costs. The SLR5500 and SLR8000 series repeaters are made up of the following FRUs:

• Modem FRU
• Power Amplifier (PA) FRU
• Power Supply (PSU) FRU
• Front Panel FRU

The SLR 8000 series also has an optional Wireline Board FRU.

FSM

FSM (Finite State Machine) is a type of conceptual model used to design and describe computer programs or electronic systems.

FSN

FSN stands for Fragment Sequence Number and is an information element used in DMR system, primarily for managing the segmentation and reassembly of longer data messages.

The FSN information element is used to consecutively number confirmed data message fragments that collectively form a longer confirmed data message. It is also transmitted in single fragment unconfirmed and confirmed data messages. The FSN field is 4 bits in length.

For multi-fragment confirmed data messages, the FSN field is divided into two parts: a flag and the sequence number. The Most Significant Bit (MSB) of the 4-bit FSN field acts as a flag and, if the MSB is asserted (1xxx2), it indicates the last fragment in the chain but if it is cleared (1xxx2), it indicates a subsequent fragment (i.e. this is not the last one).

The three least significant bits are used for the sequence number of the fragments. The sequence numbering starts from 000₂ for the first fragment and cycles from 0012 to 1112. When the number reaches 1112, the next increment is 0012.

The FSN field is also used to uniquely identify single data packets. A logical message composed of a single physical confirmed data message (or packet) shall have an FSN value of 10002. For an unconfirmed data single fragment, the FSN value is 00002.

The FSN information element is accepted by the receiver if the Re-Synchronize Flag (S) is asserted. When the S bit is asserted, it effectively disables the rejection of duplicate messages.

FULL LC

FULL LC stands for Full Link Control and is a type of Link Control message defined in ETSI TS 102 361. The Full Link Control message (FULL LC) contains a 72-bit information field and contains 7 octets of data. The FULL LC PDU structure contains control and feature elements, including the Full Link Control Opcode (FLCO) and the Feature set ID (FID) combination.

The total length of the FULL LC PDU varies depending on where it is transmitted:

• 96 bits for header and terminator bursts (which includes the 72-bit LC field plus a 24-bit Reed-Solomon CRC).
• 77 bits for embedded signaling (which includes the 72-bit LC field plus a 5-bit Checksum (CS)).

The FULL LC message is designed to be carried by various bursts and PDUs:

• Headers: Specifically, the Voice LC Header uses the FULL LC PDU to indicate the beginning of a voice transmission and carry addressing information.
• Terminators: The Terminator with LC uses the FULL LC PDU to indicate the end of transmission and carry control information. This includes the Terminator Data Link Control (TD_LC) PDU used in data protocols, which conforms to the LC format structure defined in figure 7.1 of ETSI TS 102 361-1.
• Embedded Signaling: FULL LC messages are also embedded within voice and data traffic.

For voice bursts, the 72-bit LC message, after encoding and fragmentation, fits into the embedded field of four bursts within a voice superframe.

The contents of the FULL LC message include information elements necessary for call setup and feature identification. These include:

• Feature elements such as Full Link Control Opcode (FLCO) (6 bits) which identifies the over-air facility or feature; Feature set ID (FID) (8 bits) that identifies the feature set (Standard or Manufacturer's) and full LC Data (56 bits) which contains feature-specific information such as Source ID and Destination ID.
• Message dependent elements such as Protect Flag (PF) (1 bit); Reserved (1 bit).; Full LC CRC or Checksum, used for error protection (24 bits for header/terminator, or 5 bits for embedded signaling).

Several specific PDUs utilize the FULL LC structure:

• Group Voice Channel User (Grp_V_Ch_Usr) LC PDU.
• Unit to Unit Voice Channel User (UU_V_Ch_Usr) LC PDU.
• GPS Info LC PDU.
• Talker Alias header LC PDU.
• Talker Alias block LC PDU.
• Terminator Data Link Control (TD_LC) PDU.

G

Gen

Generation (Gen) is defined in ETSI TS 102 361 as an information element with a length of 5 bits. It is used in DCDM (simplex) Wide Area Timing (WAT) signalling to indicate the Number of timing hops from the leader. A value of 000002 indicates that this radio is the wide area timing leader or that the wide area timing leader is unknown.

The Gen element is contained within the Channel Timing CSBK (CT_CSBK) PDU. When a non-timing-leader radio accepts a new wide area timing leader, its internal MS_Gen parameter is set to one more than the received Gen value. During the process of a new channel acquisition (power up or channel change) in TDMA direct mode, the radio initializes its internal MS_Gen parameter to 0.

The Gen value is used in the CT_CSBK Evaluation (CCE) process by a radio to resolve DCDM timing leader conflicts; specifically, if the received Leader Wide Area Timing IDentifier (LWATID) equals the receiver's MS_LWATID; the received Sync Age (SA) equals the receiver's MS_SA and the received Gen is less than the receiver's MS_Gen. In this case, the radio accepts the channel timing and sets MS_Gen to one more than the received Gen value.

Gen_Site_Params

Gen_Site_Params (General Site Parameters) refers to a type of Announcement PDU transmitted by a Trunking System Control Channel (TSCC) in an DMR Tier 3 system. Since it is a broadcast PDU, it carries information relevant for all radios and includes information like current site and network information.

GF

Galois Field (GF) is a mathematical structure utilized in Forward Error Correction (FEC) and Cyclic Redundancy Checksum (CRC) calculations.

GN

GN stands for Group Number, a component used in defining the Fleet Group Identity of a Talkgroup when MPT1343 numbering is used. When expressed as part of the complete Group Identity structure, the GN consists of 3 digits in the range between 900 and 999. Hence every group fleet consists of 100 Group Numbers (GN) and 7000 for each Network Prefix (NP).

The complete 8-digit structure of the Fleet Group Identity consists of three parts, using concatenation: NP (3 digits) FGN (2 digits) GN (3 digits). FGN is the Fleet Group Number. A shortened 3-digit group identity is represented simply as GN (3 digits).

The relationship between the Network Prefix (NP), Fleet Group Number (FGN), GN, and the Call User Address Identity (CAI) address (used in the Air Interface) is defined by a conversion algorithm:

$ID=((NP-328)*8000)+((FGN-20)*100)+((GN-900)*100)+100$

GNSS

GNSS (Global Navigation Satellite System) is the collective term for any satellite-based system that provides autonomous geo-spatial positioning with global coverage, including well-known systems like the U.S.'s GPS, Europe's Galileo, China's BeiDou, and Russia's GLONASS. GNSS receivers use signals from these constellations of satellites to determine a receiver's location on Earth. Accessing multiple satellite systems provides redundancy and greater accuracy, as receivers can select the best available signals, improving reliability even when signals are obstructed.

See GNSS for more information.

GOB

The MOTOTRBO Generic Option Board (GOB) is a hardware expansion for select Motorola MOTOTRBO radios. It's a small circuit board that uses either one of the following chipsets:

• GOB1.5 Chipset (DP/DM series): This chipset includes an Atmel AVR32UC3B0512 microprocessor, a 64Mbit serial flash, and a 3-axis accelerometer.
• GOB3.0 Chipset (R7): This chipset includes a Cypress S25FS064S microprocessor, a 64Mbit serial flash, and a 3-axis accelerometer.

It fits into a dedicated slot within the radio, extending its capabilities beyond what the radio can do on its own. The GOB acts as a controller of the radio, enabling it to run specialized software applications developed by Motorola Solutions Application Partners.

Software applications running on the Generic Option Board can unlock a variety of advanced features, including:

• The board can store large numbers of GPS coordinates (up to 500,000 or more) and then send them in a compressed batch when the radio channel is back within network coverage, or this data can be downloaded using a USB cable.
• The board can use internal sensors to detect unusual tilt angles or a lack of movement, triggering an emergency alarm. It can be programmed to expect a user check-in at regular intervals and trigger an alarm if the check-in is missed. Using acceleration data, it can detect a sudden and strong impact, such as a vehicle crash, and automatically send an alert.
• The GOB can support more complex telemetry applications, allowing for the monitoring and control of external sensors and devices.
• The board can automatically switch the radio's channel based on its GPS location, ensuring the user is always on the correct channel when entering or leaving a specific coverage area.

The MOTOTRBO Generic Option Board is compatible with specific MOTOTRBO radio series, such as the MOTOTRBO R7 and the 4000e series (DP4000e, DM4000e, DP3000e). It's important to note that a specific GOB model is often designed for a particular radio series and may not be compatible with others. For example, some GOBs for the R7 are not compatible with the DP4000e series.

The development and deployment of applications for the GOB are a specialized process. Access to the necessary API) and tools requires membership in the Motorola Solutions Application Developer Program.

GPIO

General Purpose Input Output - see GPIO.

GPI

In DMR Tier 3 systems GPI refers to an identifier for a system entity serving as a Gateway Address when calls are being diverted. The DMR ID (Radio ID) value associated with the GPI address is FFFECE16. When a radio uses the Call Diversion Service to divert calls intended for a talkgroup, the GPI address is used as the Target_address or Gateway information element in the C_RAND (Random Access Request) PDU. If a radio is sending the diverted address information to the TSCC (Trunking System Control Channel) during a Call Diversion service setup (using the UDT mechanism), the GPI address is listed as the destination gateway when diverting to a talkgroup address.

GPS

See GNSS.

GRE

Generic Routing Encapsulation (GRE) is a tunneling protocol developed by Cisco Systems that can encapsulate a wide variety of network layer protocols inside virtual point-to-point links or point-to-multipoint links over an Internet Protocol network.

In turn, GRE tunnelling is a method of creating virtual, point-to-point connections over an IP network by encapsulating original data packets within new, outer IP packets. This process allows different network protocols to be transported across a network that would otherwise not support them, creating a tunnel between two endpoints, such as routers. GRE tunnelling provides a simple, generic way to transport various types of network traffic, though it doesn't inherently provide encryption like IPsec does.

With GRE Tunnelling, the original data packet, which could be in a different protocol like IPv4, is wrapped inside a new GRE header. This new GRE packet is then placed inside an outer IP packet which is routed across the intervening IP network, transparent to the routers in between, which only process the outer (IPv6) header. At the destination endpoint, the GRE and outer IP headers are removed, and the original data packet is forwarded to its intended destination.

GRE is often used to allow networks that use different protocols (e.g., IPv4 and IPv6) to communicate with each other; to create a direct, virtual connection between two networks that are physically separated by another IP network or to carry traffic from protocols not supported by the network infrastructure.

Grp_V_Ch_Usr

Grp_V_Ch_Usr is a specific type of Link Control (LC) Protocol Data Unit (PDU) used to establish and manage group voice calls. Its Full Link Control Opcode (FLCO) value is 0000002.

Call Initiation (Beginning Of Call - BOC/BOT): The first burst transmitted at the Beginning Of Transmission (BOT) (which may be the BOC) carries this LC Message using the Voice LC Header Data Type burst. This transmission conveys the necessary addressing information to notify the selected group of the call.

Late Entry: This LC Message is repeatedly transmitted by embedding the Link Control (LC) information into the voice bursts themselves. This mechanism facilitates late entry into a call for Mobile Stations (MS) that are scanning, powering on during a transmission, or failed to decode the initial voice header.

Call Termination (End Of Transmission - EOT): The Group Call End Of Transmission (EOT) is signaled by sending the Grp_V_Ch_Usr LC Message using the Terminator with LC Data Type burst, following the transmission of the last voice superframe.

Other Services: This PDU is also used, with address modifications, for Unaddressed voice call service and All call voice service. For an unaddressed call, the group address in the Grp_V_Ch_Usr PDU is set to one of the reserved Unaddressed Call values. For an all call (broadcast), the group address is set to one of the reserved All Unit IDs values (like ALLMSID), and the Service Options Broadcast Field within the PDU is set to 12 to indicate a one-way voice call with no call hangtime.

The Grp_V_Ch_Usr PDU consists of 9 octets in total (Octets 0 and 1 for the Link Control format structure, and Octets 2 to 8 for specific information). The message dependent and feature elements include:

Information element	Length	Remark
Protect Flag (PF)	1 bit
Reserved	1 bit	Shall be set to 0₂
Full Link Control Opcode (FLCO)	6 bits	Shall be set to 000000₂
Feature set ID (FID)	8 bits	Shall be set to 00000000₂
Service Options	8 bits	Includes parameters like the Open Voice Call Mode (OVCM) bit and Priority level.
Group address	24 bits	The destination address for the group call.
Source address	24 bits	The individual address of the transmitting entity.

GUI

A GUI (Graphical User Interface) is a way to interact with a computer or device using visual elements like icons, buttons, windows, and menus, rather than typing text commands. It uses a point-and-click system with a mouse or touchscreen to make software and operating systems easier and more intuitive to use for people without programming expertise.  

H

H

In ETSI TS 102 361, H is used as an abbreviation in the context of coding and modulation.

Hamming parity bits (H)

H refers to the Hamming parity bits. These parity bits are used in various error correction schemes utilized in DMR signalling.

Deviation Index (h)

In the context of 4FSK modulation, h is defined as the deviation index for 4FSK modulation. The deviation index, h, for 4FSK is defined to be 0,27. This value is used in the calculation of maximum deviation D for a symbol.

H_Cx

H_Cx stands for a Hamming parity bit from column x of a BPTC.

H_Rx

H_Rx stands for a Hamming parity bit from Row x of a BPTC

HHCH

A HandHeld Control Head is an optional accessory used with the DM4000e series that allows the user to access the radio controls from the microphone (the handheld control head itself). It's particularly useful where the radio unit cannot be installed in an accessible location or the user is not close to where the radio must be installed. The HHCH is essentially a single unit that combines the functions of a remote control panel and a microphone. The user holds it in their hand, much like a traditional two-way radio.

The HHCH allows the main radio transceiver unit to be installed in a convenient but out-of-the-way location, such as under a seat, behind the dash, or in the boot of a vehicle. The HHCH itself is then mounted closer to the user, for example, on a standard clip by the driver's seat. It HHCH connects to the main radio unit via a coiled cord, which can stretch to allow the user to move around the vehicle while still having full control over their radio.

The HHCH connects to the radio via the control head connector which means the standard control head must be removed and replaced with a special plate with the socket on it.

High_Comp_Ch

High_Comp_Ch is a Layer 3 constant that defines the highest logical channel in use by a DMR Tier 3 network. It specifies the highest logical channel in use by the network. Its value ranges from the Low_Comp_Ch value up to 4095. The value of High_Comp_Ch, along with Low_Comp_Ch, defines the range of possible physical channel numbers utilized during a comprehensive hunt sequence.

The comprehensive hunt sequence is a procedure where a radio samples all possible physical channel numbers within the range set by these two values. It serves as a contingency to allow Trunk Station Control Channels to be acquired even if channels not normally employed are in use.

Also see Low_Comp_Ch

HI_RATE

HI_RATE is a 1-bit information element used in packet data communication to indicate the requested data transmission mode. It specifies the preferred data transmission mode requested by a radio or expected by a repeater/trunking controller for packet data.

02 indicates that the payload channel uses single slot data.

12 indicates that the payload channel uses dual slot data.

HI_RATE is included in the Service_Options section of PDUs related to packet data services, such as:

• C_AHOY PDUs transmitted by the TSCC to the called radio during call setup for a packet data call service.
•  C_RAND PDUs sent by the radio in a random access request for a packet data call service.
• TD_GRANT PDUs used in Duplex Private Data Channel Grant CSBK/MBC PDU to indicate that the Duplex Payload Channel always uses single slot data.

High-rate transmission uses dual slot data timing, while single slot data timing is also defined. The ability to choose between single slot and dual slot modes affects the bit rate offered to upper layers of the DMR stack, although the format of the carried messages remains unchanged.

HMAC

HMAC, or Hash-based Message Authentication Code, is a cryptographic technique that verifies both a message's integrity and its sender's authenticity using a secret key and a hash function. By combining these elements, HMAC creates a unique authentication code for a message, ensuring that only authorized parties with the correct key can generate and verify it, thus preventing unauthorized modifications.

HMAC is implemented in various MOTOTRBO systems to provide optional packet authentication over the back-end network. Its primary purpose is to prevent an attacker impersonating a MOTOTRBO infrastructure element (e.g. repeater or application) in order to gain access to the system.

HMAC authentication is optionally offered by:

• An IP Site Connect (IPSC) system for authenticating packets sent over the back-end network between IPSC devices.
• A Capacity Plus Multi Site (CPMS) system for authenticating packets sent over the back-end network between repeaters and host PCs.

HMAC is used to create a cryptographic signature for each packet and utilizes the SHA-1 algorithm and a 20-byte long symmetric key. To save bandwidth across the back-end network, this 20-byte signature is truncated to 10 bytes before being attached to the packet.

If a customer chooses to use this feature, they must manually configure the same key on all the relevant system entities/devices. Neither the IPSC system nor the CPMS system supports remote rekeying for HMAC.

The HMAC authentication mechanism does not protect against replay attacks. For more secure communication, it is recommended that the IPSC or CPMS systems use Secure VPN routers to connect over the back-end network. If Secure VPN routers are employed, they can optionally provide confidentiality of all messages (including system messages, control messages (CSBK), and voice or data headers). In this case, the use of the HMAC mechanism becomes redundant, and it is recommended that it be disabled to save bandwidth over the back-end network.

In addition to the above, the HMAC approach using Secure Hash Algorithm (SHA) is assumed in specific IPsec tunnel configurations used for capacity planning, such as GRE with IPsec AH (Authentication Header) and GRE with IPsec ESP (Encapsulating Security Payload).

HMSC

HMSC is an abbreviation for High level Message Sequence Chart. It is used in ETSI TS 102 361 and serves as a high-level illustration detailing the procedures and interactions within a DMR system.

Hx

Hx stands for a Hamming parity bit for row x of a BPTC.

I

ICMP

ICMP is used in MOTOTRBO systems to some extent. For example, if the MOTOTRBO Network Interface Service (MNIS) is unable to route a data message (e.g. due to a loss of connection with the repeater system or another error condition), the data message is dropped, and an ICMP message is returned to the data application.

Although not natively supported, ICMP ping can be used to determine whether there is data connectivity between an application like MOTOTRBO Radio Management (specifically the Device Programmer and/or MNIS) and the radio. To overcome the lack of packet scheduling in a DMR system, he -w switch needs to be added to the ping command and a value of 5000ms or more needs to be specified:

ping 12.nnn.nnn.nnn -w 5000

nnn.nnn.nnn is the DMR ID of the radio expressed as three octets. 12 is the default CAI. For example, the IP address of Radio ID 2626054 would be 12.40.18.6.

ID

ID either refers to the DMR ID or Wide Area Timing Identifier.

DMR ID

The DMR ID; Radio ID or talkgroup ID and is a number used to address individual radio units, groups of radio units, or various fixed gateway entities that provide network services.

The DMR ID is a 24-bit Air Interface (AI) address. DMR IDs are fundamental to the Call Control Layer (CCL) (Layer 3) protocol, which is responsible for control of the call, including addressing and facilities. The 24-bit AI address is split into two parts: the first 9 bits represent the Network Area Identity (not to be confused with NAI), and the remaining 15 bits represent either the Short Subscriber Identity (SSI) (for individuals) or Short Group Identity (SGI) (for talkgroups).

DMR IDs fall into three main categories: Individual Addresses, Group Addresses (Talkgroups), and special Gateway/Service Identifiers:

1. Individual addresses identify a specific radio (referred to as a Mobile Station or MS in ETSI TS 102 361). Individual call addresses (for MSs) occupy the range of 1 to 16,777,215 (FFFFFF16). Radios on a DMR Tier 3 system must use a unique ID. The Logical Link ID (LLID), which is 24 bits long, identifies either the source address (the transmitting radio) or the destination address (the receiving radio or group of radios). In Link Control signalling, the Source Identifier (ID) identifies the individual address of the transmitting entity, and the Destination ID identifies the address of the receiving entity (or entities).
2. Group identities are needed for group call services. A radio may be a member of an arbitrary number of talkgroups (in a MOTOTRBO radio via the RX Group List or OVCM). Addresses used for groups fall under the Short Group Identity (SGI) category, with a range of values from 1 to 7,000 (16,777,215 in MOTOTRBO) typically representing a group identity. In DMR Tier 3 systems, calls to talkgroups are handled by the system, and a radio may be a member of one or more talkgroups.
3. The DMR specifications use many reserved 24-bit IDs, often referred to as aliases or gateway addresses, to identify network services or systems rather than individual radios. These include:

Alias	Purpose	Value (Hex)
PSTNI / PSTNDI	Gateway address for services to the Public Switched Telephone Network (PSTN), using aligned/offset timing, respectively.	FFFEC0 - FFFED0
PABXI / PABXDI	Gateway address for services to the Private Automatic Branch eXchange (PABX), using aligned/offset timing, respectively.	FFFEC1 - FFFED1
IPI / IPDI	Address for services to an IP Gateway, using aligned/offset timing, respectively. Used in IP Connection Advice procedures.	FFFEC3- FFFED5
REGI	Address used to identify a registration service.	FFFEC6
TSI	Address of the Trunk Station (TS), typically used for MS Radio Check.	FFFECA
DGNAI	Address to identify the Dynamic Group Number Assignment service.	FFFED6
ALLMSID	ID used to address all MS (AllCall) in every site in the system as a talkgroup.	FFFFFF
ADRNULL	An ID that is not assigned to any entity.	000000

The unique IPv4 address of a radio can be derived from its Data Link Layer (DLL) address, which is itself tied to the DMR ID (24-bit layer 2 address).

Wide Area Timing Identifier

It is also referred to in ETSI TS 102 361 in conjunction with the Identifier (ID) information element is part of the Wide Area Timing Identifier (WATID) and has a length of 20 bits. The ID's initial value at power up and channel change is the Source Identifier (SID), or it may be referred to as the Leader Identifier (LID) if the leader is unknown.

See WATID.

IE

An Information Element (IE) is a subset (field) within a Protocol Data Unit (PDU). Examples include: Logical Link ID (LLID); Feature set ID (FID); Service Access Point ID (SAPID); Pre-emption and power control Indicator (PI); Access Type (AT); Service_Options;    ◦ Response Delay (RD); Registration (Trunking Systems); IP_Inform and Target Address Contents (TRGT_ADR_CNTS).

IEC

The International Electrotechnical Commission (IEC) is an international standards organization that prepares and publishes international standards for all electrical, electronic and related technologies.

IETF

The Internet Engineering Task Force (IETF) is an international community of network operators, vendors, and researchers who work to develop and promote open standards used in computer networking. Their primary activity is the creation of technical documents known as Request for Comments (RFCs) which form the basis for many protocols such as UDP (RFC 768) TCP (RFC 793) IPv4 (RFC 791).

IHL

The Internet Header Length (IHL) is an Information Element (IE) used to define the length of the IPv4 header.

IN

The Individual Number (IN) is part of the addressing scheme used in some DMR Tier 3 systems when the ETSI TS 102 361-4 Annex E numbering scheme is used. It is the least significant part of the 8-digit complete MS Fleet Individual Identity. This complete identity is represented by the concatenation of the Number Prefix (NP), the Fleet Individual Number (FIN), and the Individual Number (IN).

MOTOTRBO Capacity Max does not use this numbering scheme.

It is a carry over from MPT1343.

IO

IO is an abbreviation for Input Output.

IOP

The DMRA Interoperability Process is arrangement that provides a formal and consistent test mechanism which enables competing manufacturers to test that their products are compatible. It was developed by the Digital Mobile Radio (DMR) Association to ensure that users and equipment suppliers benefit from a truly open multi-vendor market for DMR equipment. The process results in a DMR IOP Certificate and applies to the interface between two specified products and covers only the specified functions.

The IOP Process does not cover functionality requirements that do not relate to signalling interfaces, such as the user interface and language. These must be verified by other methods if required. A DMR IOP Certificate does not indicate that a product is type approved; all products must still be type approved according to local regulations.

IP

IP is an abbreviation for Internet Protocol.

IP_INFORM

IP_Inform is an Information Element (IE) used in DMR Tier 3 trunking systems during the registration process to signal the radio's intent regarding its IP connection status. If the radio registers with the IP_Inform bit set, the network (TSCC) recognizes this as an IP connection advice request and initiates a follow-up Unified Data Transport (UDT) procedure. This in turn allows the radio to upload the actual IP address information to the system using a C_UDTHU PDU.

IPDI

The International Portable DAM Identity a specialized identifiers or gateways used in data procedures on a DMR Tier 3 system.

The IPDI is the address used as the Source Address or Gateway identifier when a radio is performing IP Address registration using the Unified Data Transport (UDT) inbound channel mechanism. This procedure is part of the IP Connection Advice process, which allows the radio to advise the system of its IP connectivity status.

IPDI is a type of address associated with services to an IP gateway using payload offset timing, specifically represented by the DMR ID FFFED516 (1677691710).

IPI

Internet Protocol Identity (IPI) is an address, or gateway identifier, used for services to an IP gateway. The associated DMR ID for IPI is FFFEC316. This procedure allocates an IP address to the radio which is mapped to the radio's DMR ID.

MOTOTRBO Capacity Max uses a different method to handle IP data between a radio and gateway which is more effective and reliable.

IPSC

IP Site Connect (IPSC) is a MOTOTRBO system topology that operates as a conventional DMR Tier 2 system that provides multi-site connectivity and coverage by linking MOTOTRBO repeaters together via an IPv4 network. It combines the logical channels (time slot 1 or 2) of multiple MOTOTRBO repeaters into one logical channel that covers all those locations. The resultant coverage area of an IPSC system is the sum of the coverage areas of all the repeaters.

IPSC enables voice and data communication between two or more MOTOTRBO single site systems located at geographically separate locations, even if they operate in different frequency bands. When a call starts at one repeater, that repeater sends the voice and data packets over the backend network to all associated repeaters, which then repeat the call, a process sometimes called All sites Light-Up.

IPSC also supports automatic roaming for radios between sites.

It is important to note that while IPSC expands coverage, it generally does not increase the capacity (number of calls per hour) of the system compared to a single site configuration. Also, repeaters with overlapping coverage must use discrete transmit and receive frequencies. To prevent radios roaming to undesired sites, different Colour Codes can be used on the repeaters.

Implementing IP Site Connect often only requires software updates for repeaters and radios, along with connecting the repeaters to an IPv4-based back-end network, rather than requiring new hardware beyond network devices like routers. This backend network can be a dedicated network or the Internet provided by an Internet Service Provider (ISP).

IPsec

IPSec (Internet Protocol Security) is a suite of protocols that work at the network layer (IP layer) to provide secure communication over an Internet Protocol (IP) network. Its primary functions are to ensure confidentiality ; Integrity and authentication. It is most commonly used to set up Virtual Private Networks (VPNs) by creating an encrypted communication path called a "tunnel" over public networks like the Internet.

ISO

The ISO is the International Organization for Standardization (ISO) is an independent, non-governmental international organization that develops and publishes voluntary, consensus-based, market-relevant International standards.

An ISO file (or ISO image) is a single file that contains a complete, sector-by-sector digital copy of an entire optical disc. It is an exact replica that preserves not only all the files and folders but also the original disc's file system structure, metadata, and boot information, making it an ideal format for archiving, distributing, or replicating media. The name "ISO" comes from the ISO 9660 file system standard, which is widely used for this type of media.

ISP

An Internet Service Provider is an antiquated term for a company or organization that provides individuals and other companies with access to the Internet and other related services. Although there are today companies providing internet access, these offer many more services than just internet access.

IT

Information Technology.

J

JTP

JTP Job Tickets Protocol (Enhanced Job Tickets Protocol, EJTP) is a layer 6 protocol used in MOTOTRBO systems to facilitate message exchanges between an application and radios related to Job Tickets also known as Work Tickets. Job Tickets is a feature designed to help customers manage tasks assigned to radio users, which is particularly useful in service organizations like hotels, factories or security.

Also see Job Tickets.

K

K

In the context of MOTOTRBO systems, particularly Capacity Max, K refers to the Authentication Key. For more information see Authentication.

L

LAN

Local Area Network.

LB

The LB information element is used in various signalling messages within the DMR protocol, primarily to manage multi-block transmissions. If set to 12, it indicates that the current message is either a CSBK or the last block in a MBC.

LBT

Listen Before Transmit (LBT) is a mechanism that helps with ensuring that the channel is free before transmitting. In Digital Mobile Radio (DMR) systems, LBT is part of the channel access rules and procedures used by radios to determine if a channel is available before initiating a transmission. For services such as unconfirmed data, a Polite Type channel access mechanism (which includes LBT functionality, such as Polite to Own Colour Code or Polite to All) is used. When a Polite channel access policy is required, the radio uses an Idle Search Timer (T_IdleSrch) to determine if the desired slot is idle before granting transmission.

For more information see TX Admit Criteria.

LC

Link Control messages are a fundamental part of DMR signalling. They are used to carry information for various purposes such as

There are two main types of Link Control messages defined for signalling:

The Full LC message contains a 72-bit information field and is carried by voice and data traffic, headers, and terminators. See also FLCO

The Short LC message contains a 28-bit information field and is carried by the Common Announcement Channel (CACH). See also SLCO

For conventional systems, a Voice LC header burst is sent at the start of a voice transmission to indicate the beginning of the transmission and carry addressing information. To support late entry, LC messages are included in voice bursts. Voice transmissions are typically terminated by sending a general data burst with a Terminator with LC. The beginning, continuation, and end of a complete LC message embedded within voice bursts are framed using the Link Control Start/Stop (LCSS) bits of the EMB field.

LCP

Linked Capacity Plus (LCP), also known as Capacity Plus Multi Site (CPMS) or Multisite Capacity Plus is a MOTOTRNO trunked topology that provides both coverage and capacity. It combines the trunking features of the Capacity Plus–Single-Site and the multi-site feature of the IP Site Connect.

Key features include:

• Up to 15 sites per system.
• Up to 8 trunked channels (16 timeslots) per site.
• Up to 12 data revert channel per site.
• Does not require/use site controllers.
• Uses standard MOTOTRBO hardware.
• Supported by most MOTOTRBO radios.
• Uses many elements from DMR but is Motorola proprietary.
• It is a trunked solution in that the payload (traffic) channel is automatically allocated by the system but is not like Capacity Max in that it does not support call queuing; priority and pre-emption.

See Multisite Capacity Plus for more details.

LCSS

Link Control Start/Stop (LCSS) is a 2-bit information element found in the Embedded Signalling Field (EMB) of DMR bursts. Its primary function is for framing LC or CSBK signalling, indicating the start, continuation, or end of a message.

Value	Remark	Usage
00₂	Single fragment LC or first fragment CSBK signalling.	Indicates a message that fits entirely within one embedded signalling opportunity (Single fragment LC), or the first portion of a multi-fragment CSBK signalling. Note that there is no Single fragment LC defined for Common Announcement Channel (CACH) signalling. Non-LC embedded signalling types, such as Reverse Channel (RC) information, are also indicated by setting the LCSS bits to "Single Fragment LC Packet".
01₂	First fragment of LC signalling.	Indicates the beginning of a Link Control message that spans multiple bursts.
10₂	Last fragment of LC or CSBK signalling.	Indicates the termination of a multi-fragment LC or CSBK message.
11₂	Continuation fragment of LC or CSBK signalling.	Indicates that the message fragment being carried is neither the first nor the last portion of a multi-fragment LC or CSBK message.

LC messages are typically carried in the embedded field of four voice bursts within a 6-burst voice superframe to facilitate late entry into a call. The LCSS bits frame the beginning, continuation, and end of this complete LC message embedded within the voice bursts.

LDI

Leader Dynamic Identifier (LDI) is a 2-bit information element used in DMR signalling. Its purpose is to denote a radio's ability and preference to serve as a TDMA direct mode timing leader. When present, the LDI field helps define the leadership status: if the Leader Dynamic Identifier is present and set to a specific value (00₂), it indicates that the leader is unknown. The different values assigned to the Dynamic Identifier generally correspond to different levels of leader preference (Low, Medium, High).

See also AL; ANL; CC, CTO; D_Sync; DI; DMO; DCDM; Gen and LDR.

LDAP

LDAP (Lightweight Directory Access Protocol) is an open, vendor-neutral, industry-standard application (OSI layer 7) protocol used for accessing and maintaining distributed directory information services over an IP network. It is not used in DMR or MOTOTRBO as such but it may be used in relation to PC applications used with MOTOTRBO, especially those which need to authenticate logins (e.g. MOTOTRBO Radio Management).

LDR

LDR (LeaDeR) refers to the radio that establishes the timing reference for the channel slots on a DMO channel (DCDM). It part of the CT_CSBK evaluation process used by radios to determine the timing leader and ensure all units operate with the same channel slot timing.

See also AL; ANL; CC, CTO; D_Sync; DI; DMO; DCDM; Gen and LDI.

LE

LE either refers to Late Entry or Link Establishment.

Late Entry

Late Entry refers to the capability that allows a radio to join a voice call already in progress. This is necessary if the radio has just switched on; has just come into range of a system or did not correctly decode the initial voice header.

Link Establishment

Link Establishment (LE) is the protocol used in MOTOTRBO IPSC and Multisite Capacity Plus to facilitates network communication and connectivity between devices, particularly repeaters and application servers.

It used used by:

• Peer repeaters, when connecting to the Master repeater in a IPSC or MSCP system.
• Third-party applications seeking to access other Repeater Application Services.
• MOTOTRBO Network Interface Service (MNIS) connects with the repeater system by utilizing the link establishment procedure.

Repeater Diagnostics and Control (RDAC) tool uses Link Establishment to manage connections to a radio in both local and remote modes.

In IPSC (and to a lesser extent MSCP) systems, the link management process utilizes LE to maintain awareness of the presence, current IPv4 addresses, and UDP ports of all other repeaters (and devices) in the network. This feature requires the Master repeater to act as a broker of IPv4/UDP addresses.

LID

Leader Identifier (LID) is an information element that is part of the TDMA direct mode (DCDM) Wide Area Timing Identifier (WATID).

See also AL; ANL; CC, CTO; D_Sync; DI; DMO; DCDM; Gen and LDI.

LINEI

LINEI (Line Identity) is a specific address used within the DMR Tier 3 trunking protocol and is an Address for services to a Line Gateway where one end of the call is connected to a radio system that does not use DMR.

LIP

Location Information Protocol (LIP) is a protocol utilized for Location services. It is mostly used on DMR Tier 3 systems and was borrowed from ETSI TS 100 391-18-1 (TETRA). In principle, it supports both Inband Positioning Data Service and Application Data over IP Bearer Service. Unified Single Block Data (USBD) Polling Service is also supported. This allows immediate reporting of location.

Location information derived from LIP can be transported by embedded Link Control (LC) within the voice superframe during a voice call. For the USBD Polling Service, the Service Type is set to 00002.

Location services which use LIP typically use a network UDP Port of 5017.

See also LRRP.

LLC

Logical Link Control (LLC) is part of Layer 2 of the DMR Air Interface protocol. This layer can further sub-divided to separate the functionality of the Medium Access Control (MAC) and the Logical Link Control (LLC). This separation between MAC and LLC is often performed in radio air interface protocols due to the specialized nature of these two tasks. However, this separation is not sufficiently described in ETSI TS 102 361.

LLDP

LLDP (Link Layer Discovery Protocol) is a vendor-neutral protocol (defined in IEEE 802.1ab) that allows network devices to discover and share information about their identity, capabilities, and neighbours on a local area network. It operates at the data link layer (Layer 2) of the OSI model, sending periodic Layer 2 frames with information about the device, such as its system name, capabilities, and port ID, to a multicast address. This allows for automatic network topology discovery, simplified device integration, and easier management and troubleshooting in heterogeneous network environments.

LLID

Logical Link Identifier (LLID) is a 24-bit element within the Layer 2 protocol of DMR systems. It identifies the address of an entity involved in packet transfer. For example, in confirmed data delivery headers (C_HEAD PDU) and unconfirmed data headers (U_HEAD PDU), the LLID specifies the source and destination addresses.

Low_Comp_Ch

Low_Comp_Ch stands for Lowest logical channel in use by the network. It is a parameter that defines the lowest logical channel number used by a DMR Tier 3 network. The value of the Low_Comp_Ch information element ranges from 1 to 4095 and is stored in the radio's codeplug.

It is utilized as part of the "Comprehensive Hunt Sequence" procedures employed by a radio on a DMR Tier 3 systems when acquiring a Control Channel (TSCC). Comprehensive Hunt Sequence is a procedure that samples all possible physical channel numbers in use by the network, serving as a contingency to allow TSCCs to be acquired even if physical channel numbers, not normally used for control purposes, are active. The radio uses the Low_Comp_Ch parameter (along with High_Comp_Ch) to define the range of physical channels to be scanned during this hunt.

LRRP

Location Request & Response Protocol (LRRP) is the underlying protocol that handles radio location data in MOTOTRBO systems. It can be used to support communication for both outdoor (GPS) location and indoor (iBeacon based) location request/response messaging.

Location data for GPS-enabled subscriber radios may be reported upon:

• An immediate request (Single Location Update).
• A pre-defined interval (Periodic Location Updates). The fastest supported update interval is 30 seconds.
• A distance driven update.
• A GPIO event trigger (for mobile radios only).
• An emergency call.

The LRRP initiating application can request either indoor data, outdoor data, or both types of data in which case, the radio transmits a response message according to the LRRP request.

Outdoor Location data elements requested in an LRRP response include longitude, latitude, time, altitude, velocity, direction, and subscriber address (suaddr). Indoor Location (BTLE) data elements requested in an LRRP response include Universally Unique Identifier (UUID), Major, Minor, Timestamp, Tx Power, and RSSI.

LRRP uses XML to define fields and attributes within location requests and reports. To optimize the size of the XML data for efficient transport through the network, LRRP is further transcribed into MBXML (Motorola Binary XML), a format that tokenizes XML tags.

LRRP is generally sent as CSBK data. When the CSBK data feature is enabled on a channel and the location request contains a LRRP token for the CSBK location feature, the LRRP (GPS) message with location data is sent as a CSBK. The LRRP (GPS) message without location data (such as an LRRP triggered answer) is also sent as CSBK, unless the message is too large to be carried in a single CSBK, in which case it is sent as a DMR data packet. The LRRP server determines if a radio has the capability to transmit the LRRP report as CSBK data via the Automatic Registration Service (ARS) registration.

MOTOTRBO radios support stored persistent LRRP updates based on the Application Server request. When Persistent LRRP Requests is enabled, the radio begins sending LRRP responses upon power-up without receiving a new LRRP request. This functionality helps reduce the channel loading when a large number of radios are turned on simultaneously.

A radio can only have one periodic LRRP request active at a time. If persistence is enabled and a new periodic request is needed, a Triggered-Location-Stop-Request must be sent from the application to cancel the previous request.

The LRRP feature uses scheduled transmission windows, and the size of this window (WindowSize) is related to the amount of data requested by the location server (LRRP Response Size). If a radio is out of range, the repeater has a mechanism to free up the reserved windows, waiting a period dependent on the cadence rate of the radio's location response before de-allocating these windows

LSB

Least Significant Bit.

LWATID

Leader Wide Area Timing IDentifier is an element in TDMA direct mode wide area timing, used to synchronize multiple radios operating across an extended geographical area. It identifies the specific MS unit that is currently acting as the wide area timing leader for the system, which establishes the channel slot timing boundaries.

Every radio operating on a DCDM channel maintains its own locally stored value of this identifier, referred to as the MS_LWATID. When a radio receives timing information (such as in a CT_CSBK), the received LWATID is evaluated against the MS_LWATID to determine whether a new leader should be accepted, and if so, the radio updates its MS_LWATID and adjusts its timing accordingly.

M

MCDD

The Multi-Channel Device Driver was a variant of the MOTOTRBO RNDIS driver for Microsoft Windows. It allowed more than one Control Station to be connected to a computer at the same time via USB.

The MCDD has since ben replaced by MNIS which allows multiple data sessions on a supported system. The maximum number was 16.

Although it was called a driver, in effect, it was an application that ran as a service and routed outbound data to the correct Control Station by creating a more complex routing table.

12.0.0.0    255.255.255.0   192.168.10.2    100
12.0.1.0    255.255.255.0   192.168.11.2    101
12.0.2.0    255.255.255.0   192.168.12.2    102
12.0.3.0    255.255.255.0   192.168.13.2    103

The above is only an excerpt and there would have been rules for the 14.0.0.0/8 and 13.0.0.0/8 subnets.

The first entry directs any data with a destination address between 12.0.0.1 and 12.0.0.254 to 192.168.10.2. This is the IP address assigned to the host computer by the MOTOTRBO radio when it connects via USB/RNDIS. 100 is the interface metric.

Similarly, the second entry directs any data with a destination address between 12.0.1.1 and 12.0.1.254 to 192.168.11.2. This Control Station needed to have its address changed to 192.168.11.1 (CPS/RM).

MDC

MDC1200 is a digital signalling technology used in analogue two-way radio systems to send short data bursts for functions like PTT-ID; selective calling and emergency alarms. Oringinally developed by Motorola, it is a reliable system that transmits data at 1200 bits per second using FFSK. This allows radio users to be identified and alerts to be sent to selected radios or groups of radios.

See MDC1200.

MFID

The Manufacturer's Feature set ID is an 8-bit information element (IE) used to identify a manufacturer-specific feature set. This mechanism allows manufacturers to define and implement private feature sets that contain additional so-called private services and facilities that are not standardized by ETSI.

The Feature set ID (FID) field in DMR signaling PDUs (like the Full Link Control (FULL LC) PDU, CSBK, and certain data headers) is used to specify whether the message relates to standard features (SFID) or proprietary features (MFID). The MFID occupies a specific range of values within the 8-bit Feature set ID (00000100 - 01111111) as well as a reserved range for future allocation starting at 10000000. The standardized feature set (SFID) uses the value 00000000.

Features that are not standardized in ETSI TS 102 361 must be accessed exclusively via an alternative MFID. This distinction helps maintain interoperability at the air interface for standard features. The FID redefines Full LC and CSBK PDUs but does not redefine the Embedded Signalling Field (EMB) PDU.

ETSI is the central body responsible for managing the allocation of MFID values and manufacturers may use multiple MFID values. Similarly, multiple manufacturers or designers are even allowed to use the same MFID value, if suitable for the requesting manufacturer.

MMI

Man-Machine Interface is a string of numbers entered on a radio to perform specific functions. It can also refer to the HMI (Human Machine Interface) which describes the presentation layer (GUI) used on a radio or system.

MNIS

MNIS (MOTOTRBO Network Interface Service) is a Windows service application which supports data transfer between PC-based applications and MOTOTRBO radios. It would be used in systems where a Control Station cannot be used or is not needed.

For more information, see MNIS.

MODEL

Within the context of DMR Tier III trunked networks, MODEL is an information element (IE) used to structure the System Identity Code (C_SYScode), which is transmitted frequently by a Trunked Station Control Channel (TSCC).

For more information, see C_SYScode.

MPLS

Multiprotocol Label Switching (MPLS), is a networking technology that directs data traffic using short path labels instead of network addresses to speed up and improve network performance. Instead of each router inspecting an IP address, MPLS assigns a label to a packet at the network's edge, and subsequent routers forward the packet based on this label along a pre-determined path. This makes forwarding decisions faster and more efficient, and the technique can also be used to prioritize certain types of traffic.

MS

Mobile Station is the term used in ETSI TS 102 361 to describe a radio - either mobile or portable (handheld).

MSB

Most Significant Bit.

MSTP

Multiple Spanning Tree Protcol.

MTU

Maximum Transmission Unit.

MV_AP

Move Absolute Parameters (MV_AP) is an Appended Multi Block Control (MBC) Protocol Data Unit (PDU) used for the Move TSCC (Trunk Station Control Channel) operation.

It is the second block (continuation block) of a Multi Block Move MBC message transmitted by the Trunked Station (TS) and carries absolute frequency relationship information required to instruct a radio to move to a new TSCC.

Capacity Max does not use this.

N

NA

Not Applicable.

NACK

Negative ACKnowledgement (NACK) is a message which indicates that a received message or requested service was unsuccessful, refused, or terminated. NACK Protocol Data Units (PDUs) are identified by the tt (ACK type) bits being set to 002

Directional Variants and Usage:

1. C_NACKD (Negative ACKnowledgement Outbound):
   • Transmitted by the Trunked Station (TS) or TSCC (Control Channel) to the radio.
   • It is used to inform the calling MS that its service request failed or was refused, providing a Reason code for the failure.
   • The TSCC also sends a C_NACKD as a Mirrored_Reason to the calling party, echoing a rejection reason originally provided by the called MS (C_NACKU).
2. C_NACKU (Negative ACKnowledgement Inbound):
   • Transmitted by the Mobile Station (MS) to the TSCC.
   • It is used by the MS to reject or refuse a service demanded by the TS (e.g., rejecting an incoming call or a Stun/Revive request).

Contexts where NACK is used:

• Registration: If a registration request is unsuccessful, the TSCC sends a C_NACKD with specific reasons like Reg_Refused or Reg_Denied.
• Call Setup: C_NACKD terminates a call attempt if resources are unavailable, the call is refused, or the called party is busy.
• Data Services: In the confirmed data bearer service (using Selective Automatic Repeat reQuest or SARQ), a NACK response can signal specific failures such as illegal format, CRC failure, or that the memory of the recipient is full.
• Feature Refusal: If a radio requests a feature the network does not support, the TSCC may respond with a C_NACKD (Reason = Not Supported).

NACK_Rsp

See NACK.

NACKD

See NACK.

NACKU

See NACK.

NAI

The Network Application Interface (NAI) is an interface and feature of a MOTOTRBO system that enables connectivity for external applications through the repeaters.

It is used by MNIS to communicate with repeaters and facilitate data transmission and reception between data application servers and MOTOTRBO radios. When a data application sends a UDP/IP data packet, MNIS encapsulates it in a Network Application Interface packet before sending it to the repeater for Over-The-Air transmission, and the repeater performs the reverse when sending data back to the MNIS.

To allow MNIS to interface with a repeater, the Network Application Interface for Data feature licence must be purchased and enabled. If using MNIS with systems like IP Site Connect or Capacity Plus (Single or Multi Site), ideally all repeaters must have this feature enabled.

NAI also functions as a wireline interface for voice and control for third-party voice and control applications. For this a seperate feature licence - Network Application Interface for Voice Control - must be purchased and enabled.

Capacity Max does not require a NAI licence per repeater but rather a single Data Licence per MNIS instance. For voice and control, a VRC licence (one per CMSS) is needed in addition to one or more Talkpath licences.

NAT

Network Address Translation.

NBI

Northbound Interface.

NDEG

In DMR systems which support NMEA, NDEG is an information element used specifically within the structure of NMEA (National Maritime Electronic Association) formatted location data

NET

NETwork. See C_SYScode.

Nibble

Four-bits of a byte. See Nibble.

NL

New Leader (NL) is a 1-bit information element (IE) used in the Channel Timing Control Signalling Block (CT_CSBK) PDU with TDMA Direct Mode (a.k.a. Dual Capacity Direct Mode) operations on a simplex channel. It is used to manage the process of establishing and maintaining the synchronization leader when DCDM is used.

NMEA

The National Marine Electronics Association (NMEA) is a US-based marine electronics trade organization setting standards of communication between marine electronics. ETSI TS 102 361 refers to this as NMEA 0183 can be used to send location data to a tracking application. See NMEA 0183 for more information.

NMINF

NMINF stands for Latitude Fractions of minutes and is used in NMEA 0183. NMINmm works alongside other latitude components previously discussed, such as NDEG (Latitude Degrees) and NMINmm (Latitude of minutes) See NMEA for more information.

NMINmm

The abbreviation NMINmm stands for Latitude Minutes. NMINmm works alongside other latitude components previously discussed, such as NDEG (Latitude Degrees) and NMINF (Latitude Fractions of minutes).

NP

he Network Prefix (NP) is part of the structure used to define the Air Interface User Address (which is 24 bits long) in DMR Tier 3 systems that use Annex E (MPT1343) numbers.

NRand_NE

Number of random access attempts for an emergency priority service is a control plane constant that defines the maximum number of times a radio will attempt to send a random access request when initiating a service that has emergency priority.

NRand_NR

Number of random access attempts for a normal and high priority service (NRand_NR) is a control plane constant used by a radio to determine the maximum number of times it may attempt a non-emergency random access request to the network.

NS

NS (North South) is an information element used in location reporting using NMEA 0183 (National Maritime Electronic Association) formatted data. See NMEA.

NSYSerr

Number of C_SYScodes received that differ from the value verified is a threshold value used by a radio to determine when it should stop relying on the current Trunk Station Control Channel (TSCC) due to network instability or signal degradation.

NTP

Network Time Protocol.

NW

Wait Number is used the system's addressing and signaling.

While the term NW itself is listed in ETSI TS102 361 as Wait Number, the functional constant that dictates waiting behavior in response to channel access requests, is typically referred to using similar mnemonics, such as N_Rand_Wait.

N_Rand_Wait is an element used by the Trunk Station Control Channel (TSCC) to specify the delay (in TDMA-frames) a radio should wait before attempting to retransmit a random access request. The radio uses this value to derive the number of TDMA-frames, N_Wait by which the TSCC's response may be delayed.

N_Maint

N_Maint is the number of P_MAINT PDUs transmitted by a radio in order to clear down the payload channel.

OACSU

Off Air Call SetUp (OACSU) is one of the two defined methods for initiating an Individual Call service on a DMR Tier 3 system - the other being FOACSU. When used, the source (calling) radio attempts a presence check of the target (called) radio before a traffic (payload) channel is assigned to the call parties. If the source radio receives an acknowledgment that accepts the call, it then proceeds with the call using the Press And Talk Call Setup (PATCS) method (using impolite channel access). The PATCS method is considered a subset of the OACSU method.

Octet

The octet is a unit of digital information in computing and telecommunications that consists of eight binary bits. In DMR, data elements and payloads within signalling blocks and packets are frequently structured and measured in octets, these include things like Header Blocks; Data Blocks and Link Control (LC) messages.

Octets are used to define the location of specific bits within a PDU. For example, in the Channel Timing CSBK (CT_CSBK) PDU, the most significant bit (MSB) of the Leader Identifier is located in octet 4 bit 7, and its least significant bit (LSB) is located in octet 6 bit 3. When a datagram is broken down for transmission, it is split into fragments, and each fragment is further split into blocks, with each block containing a specific number of data octets.

Many DMR protocol fields are multiples of 8 bits and thus correspond directly to octets, such as the 8-bit Service Options information element.

See also Octet (Computing)

OPCODE

OPCODE (Operation Code) is an information element used in Digital Mobile Radio (DMR) protocols to specify the function or type of a given PDU; CSBK; MBC or UDT header. It is essentially a code that identifies the "over-air" facility or service being transmitted within a specific message format.

OS

Operating System.

OSPF

Open Shortest Path First (OSPF) is a routing protocol for Internet Protocol (IP) networks. OSPF works by gathers link state information from available routers and constructs a topology map of the network. The topology is presented as a routing table to the internet layer for routing packets by their destination IP address.

See Open Shortest Path First

OTA

Over The Air.

OTAP

OTAP is a key feature of MOTOTRBO Radio Management (RM) that allows technical personnel to program and manage an entire fleet of radios remotely. OTAP helps overcome the difficulties and inefficiencies associated with physically programming radios, such as locating all the radio to be programmed; waiting for radios to be brought in for programming; radios mounted in difficult to reach locations. OTAP eliminates wasted time traveling to and from customer locations and the limit of programming one radio at a time.

By using OTAP, Radio Management offers several advantages, including writing and reading radio configurations via the radio channel/system.

Together with OTAP, MOTOTRBO Radio Management offers a number of features and services, this includes:

• Writes and reads radio configurations Over-The-Air.
• Manages up to 50,000 radio configurations (or more if SQL Enterprise is used).
• Supports group and individual archive management.
• Includes application and radio mutual authentication.
• Provides synchronized configuration switchover.
• Allows the radio user a one-time option to accept or delay the configuration update.
• Supports scheduling of OTA operations and unmanned batch processing.
• Utilizes compressed and differential configuration transfer, transferring only the differences between the RM configuration and the radio configuration.
• Is designed to allow voice traffic priority while configuration transfer is ongoing.
• Utilizes the existing Over-The-Air encryption of the system.
• Optimized performance using Presence Services.

OTAP is supported in all MOTOTRBO system architectures.

OTAP utilizes the existing MOTOTRBO IP data service to communicate with field radios OTA. Connectivity is established either through Control Stations connected via USB, or over the IP network utilizing the MOTOTRBO Network Interface Service (MNIS) Data Gateway.

Before a radio can be programmed OTA for the first time, it must be provisioned locally (wired) through Customer Programming Software (CPS), USB, or Wi-Fi. This initial step programs essential communication parameters, including the OTAP authentication key.

The radio and the RM system must be configured to share an OTAP Authentication Key. This key, along with a key ID, is the only new OTAP parameter required to be programmed in the radio initially. This mechanism ensures that only a validated RM system is communicating with a customer's radio.

OTAP uses the standard data service privacy methods (AES, Enhanced, and Basic). The Control Station or MNIS Data Gateway performing the programming must contain all the privacy keys used by the radios it communicates with. Privacy keys can be updated Over-the-Air via RM delivery.

It is highly recommended that Over-the-Air operations are scheduled during times of low traffic, when radios are stationary, and are in great RF coverage, in order to minimize the impact on system performance and transfer time.

The process of applying the delivered configuration is known as switchover. This usually necessitates a radio reset, which typically causes voice downtime for a single radio lasting approximately 20–22 seconds.

OTAP does not support radio firmware upgrades; language pack updates; tuning parameter updates; device recovery; update or download voice announcement files; radio feature license activation. Repeaters cannot be programmed remotely using OTAP but they can be reconfigured using IP. OTAP is also not supported in analogue mode.

OTAR

OTAR (Over-The-Air Rekeying) is a security feature within MOTOTRBO systems used for managing encryption keys remotely. The primary function of OTAR is to allow a radio user to request the latest encryption keys from the Key Management Facility (KMF) over the air. When the user initiates an OTAR Rekey Request, the radio sends a "Hello" message to the KMF. This "Hello" message signals the KMF to send a rekey command to the radio containing the latest encryption keys.

The Key Management Facility (KMF) consists of three elements: the radio network with MNIS being the interface to the server; a client/server software application and a KMF Crypto Card.

OTAR offers the following benefits when compared to updating keys via CPS/RM:

• The KMF-generated encryption keys are not seen by anyone.
• The KMF-generated encryption keys are truly random.
• The keys are not exposed at any point during an OTAR session.

While OTAR deals specifically with updating encryption keys, it is related to, but distinct from, Over-The-Air Programming (OTAP). If OTAP is not used, the initial set of encryption keys can be programmed in a radio using only the Customer Programming Software (CPS) after which updates can be sent via OTAR. If OTAP is used, any ongoing key management must be done from the KMF.

MOTOTRBO radios do not support the KVL5000.

OVCM

Open Voice Channel Mode (OVCM) is a supplementary voice service that allows users, who are not the explicitly addressed targets of a call, to monitor and participate in the voice channel activity. From the calling radio's perspective, OVCM provides the ability to place group and individual calls that can be listened to by third-party users (non-targeted users). Furthermore, these third-party users are permitted to become part of the conversation in progress and can also talk.

The OVCM service is achieved by using a specific bit within the Service Options information element during call setup signalling. If the OVCM bit is set to 1, the call is designated as an OVCM call. This information element is present in call set-up signalling; Voice Link Control (LC) Header; Terminator with Link Control (LC).

OVCM call modification is possible in both direct mode and repeater mode and supports both Group and Individual Calls. It does not, however, support All Calls and calls made to non-radio destinations (e.g. phone call). OVCM is also not possible with data calls.

P

P CACH

P (Payload) Common Announcement CHannel (CACH) refers specifically to the signalling portion carried by the CACH burst. The Common Announcement Channel (CACH) is a component of the outbound channel (repeater-to-radio). Each CACH consists of a burst containing 24 bits. The CACH burst is generally composed of two primary sections: the TACT bits and the signalling payload (P CACH).

Four information bits and three parity bits (7 bits total), known as the TDMA Access Channel Type (TACT) bits, are dedicated to framing and status. These bits are protected by a Hamming (7,4) Forward Error Correction (FEC) code. The remaining 17 bits of each CACH burst carry the signalling payload. The physical interleaver spreads these 17 CACH payload bits (labelled P16 through P0) sequentially into the gaps of the CACH burst alongside the TACT bits for resistance to fades. Since CACH bursts occur every 30 ms, the overall payload bit rate (P CACH signalling) is approximately 566.67 bits/s (17 bits per burst).

The P CACH primarily carries low-speed signalling and channel management information. The CACH is designed to carry additional low speed signalling. Specifically, the CACH carries the Short Link Control (Short LC) message. A Short LC message utilizes the CACH, consisting of a 28-bit information field.

The Short LC Protocol Data Unit (PDU) length is 36 bits and is protected using a variable length Block Product Turbo Code (BPTC) specifically designed for CACH signalling. The resulting FEC matrix for the Short LC message is interleaved over multiple CACH bursts. Since the entire payload can be delivered in 4 CACH bursts, one Short LC message can be sent every $4*30ms=120ms$. If no CACH payload is available to transmit, a Null message Short LC shall be sent.

For DMR Tier 3 systems, the CACH is used to continuously or periodically broadcast a sub-set of the System Identity Code (C_SYScode), the Reg information element, and a Common_Slot_Counter using the C_SYS_Parms Short Link Control.

Unlike the TACT bits which have dedicated Hamming FEC within the burst, no FEC is inherently provided by the CACH for the 17 signaling bits (P CACH); instead, any FEC and CRC is part of the payload (e.g., Short LC signalling packets). The short LC message structure includes an 8-bit CRC. The Short LC payload is protected using a BPTC consisting of Hamming (17,12,3) row codes and simple parity checks for the column codes.

PA

PA can either refer to Power Amplifier or Public Address.

PABX

PABX is an abbreviation for Private Automatic Branch eXchange. PABX is referenced in ETSI TS 102 361 primarily as a type of line connected entity or gateway that allows communication between the DMR system and a private telephone network.

A PABX acts as a gateway that interfaces the DMR radio network with external wired communication systems. It serves as a system-interfaced device that is not addressable directly via the standard DMR ID. Calls can be directed to PABX extensions, just as they can be directed to subscribers on the Public Switched Telephone Network (PSTN).

The ETSI TS 102 361 protocol also permits Source Address information, such as Caller Line Identity (CLI), to be carried to the Mobile Station (MS) for calls originating from a PABX extension.

Calls to PABX extensions require a multi-part call set-up procedure because the destination address (the extension digits) cannot be accommodated in a single signalling block (C_RAND PDU). The extended addressing information (the dialled digits) is subsequently uploaded from the radio to the network (Trunked Station Control Channel, TSCC) using the Unified Data Transport (UDT) mechanism. These digits are transported as Binary Coded Decimal (BCD) digits. The Proxy Flag in the initial random access request indicates whether one UDT block (1 to 20 digits) or two UDT blocks (21 to 44 digits) are needed to transfer the PABX extension digits.

PABXDI

For calls directed from a radio to a PABX extension, specific dialling methods and addressing procedures are utilized. When an MS initiates a call to a PABX, the destination address in the DMR Air Interface signaling (specifically the initial random access PDU, or C_RAND) is set to a specific Gateway Identifier. PABXDI (FFFED116) is the gateway address used for PABX services when payload offset timing (full duplex) is used.

PABXI

For calls directed from a radio to a PABX extension, specific dialling methods and addressing procedures are utilized. When an MS initiates a call to a PABX, the destination address in the DMR Air Interface signalling (specifically the initial random access PDU, or C_RAND) is set to a specific Gateway Identifier. PABXI (FFFEC116) is the gateway address used for services to the PABX when payload aligned timing is used.

PAN

Bluetooth Personal Area Networking (PAN) is one of the profiles used for Bluetooth IP networking to with PC. Certain MOTOTRBO radios support Bluetooth and the PAN profile. Once the radio and the remote Bluetooth PC client are paired and connected using the PAN profile, the IP network connection is established. When operational, the radio acts as an access point and the peripheral as a PAN client. All data communication between the radio and the Bluetooth PC client must be addressable with an IP address and application port number over this connection.

A MOTOTRBO radio supports up to four simultaneous Bluetooth device connections, which can include the PAN profile, along with the Headset Profile (HSP), Serial Port Profile (SPP), and Fast PTT. The supported Bluetooth profiles for third-party application use are SPP and PAN.

PAR

The PARtition information element is used for controlling access across multiple control channels in a DMR Tier 3 system. Specifically, PAR is an information element used to partition radios on a control channel (TSCC). The PAR sub-field consists of two bits and part of the System Identity Code (C_SYScode).

See also C_SYScode.

PATCS

The Push And Talk Call Service (PATCS) is one of two defined methods, the other being Off Air Call SetUp (OACSU), for initiating an Individual Call or the Beginning Of Call (BOC) in Digital Mobile Radio (DMR) systems; PATCS is considered a subset of OACSU. This method transmits the necessary call setup information within the first burst at the Beginning Of Transmission (BOT).

PATCS can employ various initial channel access rules, such as Impolite or Polite to Own Colour Code, but uses an impolite mechanism while a call is in progress.

PATCS supports late entry into a call by embedding the LC information within subsequent voice bursts, which is crucial for radios joining the transmission in progress, such as those scanning or powering on. The PATCS method is also utilized for the beginning of a call when a radio is directed to a voice payload channel on a Trunked Station Control Channel (TSCC), and for individual calls initiated this way, the called party performs a radio check as part of the setup.

PC

Personal Computer.

PCR

Professional and Commercial Radio. A blanket term used to refer to Motorola Solutions radio communications equipment including MOTOTRBO. Historically, this referred to a range of analogue radio communications equipment. TETRA and Astro (P25) is not regarded as PCR.

PD_GRANT

PD_GRANT is a Private Data Channel Grant PDU. It falls under the class of Broadcast PDUs transmitted on the Trunk Station Control Channel (TSCC). This PDU is used to transfer a call to the payload channel for a private (individual) data communication. It is specifically associated with the Individual packet data Call Service (IND_D_SRV). PD_GRANT is transmitted by the a DMR Tier 3 system and addressed to an individual radio and includes both the source and destination addresses.

PD_GRANT_DX

The PD_GRANT PDU is an example of the Channel Grant PDUs transmitted by the TSCC that specifies the physical and logical channel required for the MS. If the call uses offset timing to provide a full duplex service (such as to gateways), a corresponding duplex grant, PD_GRANT_DX, is used.

PD_GRANT_MI

Private Data Channel Grant Multi-Item is a specific type of Private Data Channel Grant Protocol Data Unit (PDU) transmitted by the Trunked Station (TS) on the Trunk Station Control Channel (TSCC) or a payload channel to assign a resource for a private (individual) data communication. A multi-item data session is defined as a data session conducted over a payload channel that consists of two or more single item data sessions between communicating entities. An "item" refers to a radio payload transmission sequence that lasts from the moment the Push-To-Talk (PTT) is pressed until the PTT is released.

PDP

The primary function of the DMR Packet Data Protocol, is to enable the transfer of data messages of arbitrary length over the DMR Air Interface (AI) using a packet technique.

PDP operates primarily in the Call Control Layer (CCL), or Layer 3, which lies in the Control plane (C-plane) of the DMR protocol stack (see AI). It supports multiple Layer 3 protocols, notably Internet Protocol version 4 (IPv4), and defines strategies for Short Data Protocol (including raw data, status/precoded data, and defined data). The DMR PDP extends DMR to act as an IP subnet, which allows application programmers to develop applications in a standard environment.

Data messages handled by PDP can be sent with either confirmed delivery (requiring an acknowledgment, often using Selective Automatic Repeat reQuest or SARQ) or unconfirmed delivery (if the originator does not require an acknowledgment).

PDU

A Protocol Data Unit (PDU) is defined as a unit of information exchanged between peer protocol layer entities. In ETSI TS 102 361, the PDU serves as the fundamental container for communication, typically consisting of two main elements:

1. Protocol control information (signalling): Information necessary for controlling the communication layer or service.
2. Possibly user data: The actual content being transmitted (e.g., voice or packet data).

PDUs are often encapsulated within bursts on the Layer 2 (Data Link Layer) of the DMR Air Interface (AI). Examples of the many different types of PDUs include the Synchronization (SYNC) PDU, Control Signalling Block (CSBK) PDU, and Channel Grant PDUs.

PF

Protect Flag is a single-bit information element that is included in the format structure of various Protocol Data Units (PDUs) in ETSI TS 2012 361. It is typically found near the beginning of many Link Control (LC) PDU header blocks, such as Channel Grant PDUs and various service-related PDUs.

PHY

PHY or Physical Layer refers to Layer 1 of the DMR Air Interface (AI). It is the physical interface responsible for dealing with the actual bits and bursts transmitted and/or received. This includes things like modulation and demodulation.

PKI

A public key infrastructure (PKI) is a set of roles, policies, hardware, software and procedures needed to create, manage, distribute, use, store and revoke digital certificates and manage public-key encryption. The purpose of a PKI is to facilitate the secure electronic transfer of information for a range of network activities such as e-commerce, internet banking and confidential email. It is required for activities where simple passwords are an inadequate authentication method and more rigorous proof is required to confirm the identity of the parties involved in the communication and to validate the information being transferred.

In MOTOTRBO, PKI is used for radio regionalisation and Simple Certificate Enrolment Protocol (SCEP) needed for Wi-Fi Enterprise authentication.

PL

Private Line is an in-band analogue signalling system mainly used to support channel sharing.

PN

Presence Notifier (PN) is a service used in MOTOTRBO systems, enabling applications to obtain and track information about the presence of radios. In Capacity Max, it is implemented by the Trunking Controller on the Capacity Max System Server (CMSS) and derives both presence (whether a radio is currently registered/available) and mobility (the RF site where the radio is present) information from Over-the-Air registrations transmitted by the radio. It then informs third-party applications about these radios via the PN interface.

PN provides TCP and UDP interfaces to third-party applications that require presence information. Applications subscribe for radio presence information from the PN.

All other MOTOTRBO system topologies use Automatic Registration Service (ARS) for presence. Presence information is managed by the Device Discovery and Mobility Service (DDMS), which as the name suggests, runs as a service on a Windows PC - usually together with the application(s) requiring radio presence information.

 MNIS (MOTOTRBO Network Interface Service) requires the Device Discovery & Mobility Service (DDMS) to be installed, and ARS must be enabled in the radios for MNIS to perform mobility functions. The MNIS forwards the radio ARS message to the DDMS, which updates the radio's presence, and the DDMS notifies applications that have subscribed for presence through the watcher interface.

See also ARS; MNIS and DDMS.

POC

The Pad Octet Count (POC) is a 5-bit information element used within the Packet Data Protocol (PDP) structure in the DMR standard. It specifies the number of pad octets (bytes) that have been appended to the user data at the end of a data packet to ensure the total packet length precisely fills an integer number of data blocks for transmission. It can be found in the first header block of data packets, such as those used for unconfirmed and confirmed packet data transmission. The value of the POC is subtracted from a calculated maximum data length (which depends on the FEC coding rate used, like rate ¾, rate ½, or rate 1) to determine the actual number of user data octets transmitted.

PoE

Power over Ethernet

PPM

Parts Per Million.

PR FILL

Pseudo-Random Fill Bits PDUs are used to fill the information fields of Idle messages transmitted by a repeater when it has no other valid signalling or traffic to send. These pseudo-random bits are included only to enable continuous transmission by the repeater and are specifically not intended to be read or processed by radios. The PR FILL PDU has a length of 96 bits and is encoded using the BPTC (196,96) Forward Error Correction (FEC).

PS_RQ

Power Save_ReQuested is an information element (IE) used in DMR Tier 3 registration procedures, specifically within the Random Access Request (C_RAND) PDU. The radio will inform the Trunked Station Control Channel (TSCC) that it is requesting to activate or maintain a power save mode.

PSN

The Physical Serial Number is a 3-byte number that is factory coded into a radio. It is designed to be a non-modifiable ID associated with every device. Manufacturers must ensure it is a unique number for every device they produce and is at least 3 bytes long.

The PSN is an optional element used during radio authentication procedure on a DMR Tier 3 system. When the PSN is used, it is applied as an exclusive-or (XOR) operation on the 3-byte challenge response generated during authentication before the response is transmitted by the radio.

In a MOTOTRBO radio, the Physical Serial Number is not related to the Radio Serial Number.

PSTN

Public Switched Telephone Network. In the context of DMR, PSTN refers to an external network that the DMR system can connect to via gateways that radios can initiate calls to, alongside PABX (Private Automatic Branch eXchange) extensions or IP addresses.

PSTNDI

Used for services to the PSTN employing payload offset timing (for full duplex calls).

See also PSTN.

PSTNI

Used for services to the PSTN employing payload aligned timing.

See also PSTN.

PTT

Push To Talk.

PV_GRANT

Private Voice Channel Grant Protocol Data Unit is a PDU used on DMR Tier 3 systems belonging to the Broadcast class. It is transmitted by the system (TS) on the control channel (TSCC), usually as a single block Control Signalling Block (CSBK), to transfer an individual voice call to an allocated payload channel (traffic channel).

PV_GRANT_DX

PV_GRANT_DX (Duplex Private Voice Channel Grant) used specifically for full-duplex radio-to-radio voice call using offset timing.

P_ACKU

See P_AHOY.

P_AHOY

P_AHOY is a Ahoy Protocol Data Unit (PDU) transmitted over a payload channel as opposed to a control channel on a DMR Tier 3 system. The purpose of the P_AHOY PDU is to function as a poll or enquiry that demands a response from one or more radios. It is transmitted by the system (TS) and belongs to the AHOY class of PDUs.

The system uses the P_AHOY PDU on an active voice or packet data payload channel for various call maintenance and presence checks such as radio persence; talkgroup presence and authentication checks. P_AHOY is also used to selectively clear a specific individual radio or talkgroup from the voice or packet data payload channel, instructing the radios to abandon the channel and return to the control channel acquisition procedures (also known as the Cancel Call Service).

P_AHOY is transmitted as a single block Control Signalling Block (CSBK). The receiving radio is required to respond with an acknowledgement (typically P_ACKU) if the message is applicable to them.

P_CLEAR

Payload Channel Clear Protocol Data Unit is a Broadcast PDU transmitted by a DMR Tier 3 system (TS) on an active payload channel. Its primary purpose is to clear the call from the payload channel and is and does not solicit a response. Since it is unacknowledged, it may be repeated for reliability.

When a radio receives this PDU, it will abandon the payload channel and move to the control channel (TSCC) indicated by the PDU's channel number information.

P_CLEAR can also be used to clear all radios and talkgroups from a traffic channel (by setting the Target Address to ALLMSI) so the channel can be re-allocated, or it can be targeted to specific individuals/groups.

P_CLEAR PDUs may also be preceded by a Reverse Channel (RC) command sent by the system to forcibly cause a transmitting radio to cease transmission (MS De-key) before the final P_CLEAR clears the call.

P_GRANT

P GRANT is a Channel Grant Protocol Data Unit (PDU) transmitted by the Trunked Station (TS) on a payload channel (a.k.a. traffic channel). This PDU is utilized for several functions that include:

• Swap an ongoing call to a new payload channel.
• Announce the current call before the call's first transmission.
• Announce a new call a radio user may choose to join.

The P_GRANT PDU can be sent either as a single block Control Signalling Block (CSBK) or as a Multi Block Control (MBC) PDU. When a new call is announced via P_GRANT on a payload channel, radios have the option to leave their current call and move to the new channel or ignore the PDU; the acceptance and actioning of such P_GRANTs are manufacturer specific.

P_MAINT

The P_MAINT is a Maintenance Protocol Data Unit (PDU) transmitted by a radio on a payload channel. P_MAINT is classified as an Inbound Channel CSBK (Control Signalling Block) PDU. It is used for Call Maintenance PDUs.

The purpose of the P_MAINT PDU is to signal a Disconnect (DISCON) command, indicating the end of payload channel use.

Specific procedures involving the P_MAINT PDU include:

• When a radio (the initiator of an individual call or a talkgroup call) needs to clear down the call, it signifies the end of the call by transmitting a number of P_MAINT PDUs consecutively, and then returns to the control channel acquisition procedures.
• For a packet data call, the radio may signify the end of the call by transmitting a number of P_MAINT PDUs consecutively to instruct the Trunked Station (TS) to end the call.
• If the radio was sending voice or data frames when an overall payload call timer expired, it sends a Terminator with Link Control (LC) prior to transmitting the P_MAINT PDUs.

The P_MAINT PDU is transmitted by the radio as a single block CSBK. It contains a Maint Kind information element (3 bits). For a disconnect request, the Maint_Kind value is set to 0002 (DISCON). The Target Address is set to the TS Identifier (TSI).

The P_MAINT PDU is a key mechanism for an MS to actively disconnect from an allocated payload channel

P_PROTECT

P_PROTECT is a Broadcast PDU transmitted by the Trunked Station (TS) exclusively on a payload channel. Its primary function is Channel Protection and Access control on that channel. It uses the 3-bit `Protect_Kind` information element to perform various control functions without soliciting a response. These functions include:

1. PTT Control:
   • Disable PTT (DIS_PTT) for specific radios or a Talkgroup.
   • Enable PTT (EN_PTT) for a specific radios or a Talkgroup.
   • Enable PTT for a single MS (EN\_PTT\_ONE\_MS) radio addressed in the Target Address while disabling all other radios' transmissions. This is used, for example, after a successful payload interrupt to grant transmission to the interrupting radio.
2. Illegally Parked Radio Removal.
   • ILLEGALLY_PARKED instructs a radio whose address does not match the source or target address of the call to clear down and leave the payload channel. This is used to remove non-legitimate users from the traffic channel.
   • Since the P_PROTECT PDU is unacknowledged, the radio may repeat it at Layer 2 for reliability. It is transmitted as a single block Control Signalling Block (CSBK).

P_RAND

The P_RAND (Random Access Protocol Data Unit) is a signaling message used by a radio on the inbound channel to initiate services in a trunked system. In essence, it is the signal a radio transmits to the network when it wants to start communicating or request a resource allocation.

It carries Random Access Requests from radios to request system access to initiate various services, such as voice calls, packet data calls, or registration and is transmitted by the radio on the payload channel of a DMR Tier 3 system.

ETSI TS 102 361-4 also describes the use of a similar PDU called C_RAND (Control Random Access) which is the Random Access Request transmitted on a DMR Tier 3 Control Channel for services like call initiation and registration. However, within the context of the payload channel, P_RAND is used specifically for the include service (adding a user to an ongoing call).

P_RAND is an Inbound Channel Control Signalling Block (CSBK) PDU and the process of using it (or C_RAND) is governed by the Random Access Procedures, which, in turn, are based on slotted Aloha to control collisions, manage access delays, and ensure system stability. This procedure involves checks related to the population subdivision (Mask), service function, and whether the chosen slot is withdrawn.

All radio-initiated services in a DMR Tier 3 system begin with a Random Access attempt using the C_RAND PDU (when on the control channel) or P_RAND (when used on the payload channel for include service).

Q

QACKD

QACKD is a type of acknowledgement (C_QACKD) transmitted by the Trunked Station Control Channel (TSCC) in DMR Tier 3 systems, such as MOTOTRBO Capacity Max. It functions as a progress PDU (Protocol Data Unit) to inform a calling Mobile Station (MS) about the status of a service request, specifically indicating that the call or service request has been queued.

QR

In DMR, QR refers to Quadratic Residue. More specifically, it denotes the Quadratic Residue code parity check bit.

The Quadratic Residue (16,7,6) code is a type of error correcting code. Error correcting codes are essential in digital communication systems like MOTOTRBO to detect and correct errors that may occur during transmission over the air interface due to noise or interference. The (16,7,6) code is a shortened quadratic residue code, formed from a primitive (17,9,5) code by deleting the first two information bits and extending it by adding a single parity check bit to the end.

The Quadratic Residue (16,7,6) FEC (Forward Error Correction) is specifically used for protecting the EMB PDU (Embedded signalling PDU). The EMB PDU itself has a length of 16 bits and is placed within a burst. Its content includes the Colour Code (CC), Pre-emption and power control Indicator (PI), Link Control Start/Stop (LCSS), and the 9-bit EMB parity field, which is where the Quadratic Residue FEC is applied.

Bit Ordering: "QR" bits (QR(0) through QR(7)) are mentioned in the context of transmit bit order for BPTC (Block Parity Trellis Code) general data bursts with Reverse Channel (RC). This indicates their inclusion in the physical transmission format of data.

R

R

The letter R primarily stands for Reserved bit in the Digital Mobile Radio (DMR) Air Interface protocol.

RAN

RAN stands for Radio Area Network.

RC

The Reverse Channel (RC) is defined as a signalling burst transmitted from the target to the source (could be a radio or repeater), Its primary function is to enable a receiving unit to signal the transmitting unit during an ongoing voice or data call without interrupting the overall conversation or transmission. This feature is utilized by both Tier 2 and Tier 3 systems.

There are three defined types of RC signalling:

1. Embedded RC signalling, carried within the 48-bit embedded field of a general data burst and used on the outbound channel (repeater to radio).
2. Dedicated RC signalling, where one entire outbound channel is reserved for RC signalling.
3. Standalone RC signalling, which is used for the inbound channel (radio to repeater) as well asin in direct mode operation (DCDM). The standalone RC burst is a shortened burst containing 96 bits, which allows the radio to rapidly switch between receiving traffic and transmitting the signalling burst.

In terms of data structure, the RC PDU (Protocol Data Unit) itself has a length of 32 bits. Furthermore, the functionality of the RC often involves a Tier 2 Reverse Channel (RC) Command information element, which is 4 bits in length and can carry instructions such as transmit interrupt.

RD

The abbreviation RD stands for Response Delay. In the context of the Unified Single Block Data (USBD) Polling Service, the Response Delay information element is required for channel timing. It specifies the time duration that should elapse between receiving the end of a USBD Poll and initiating a USBD Poll Response.

RDAC

Repeater Diagnostics and Control (RDAC) is a standalone Windows application designed for system technicians and administrators primarily used to monitor and control repeaters within a system.

RDAC provides diagnostic, alarm reporting, and control functions for repeaters:

• Repeater Diagnostics allows reading information such as the repeater's Enabled/Disabled status, Analog/Digital status, Transmit Power (High or Low) status, available channels, Inbound RSSI, IPv4 address, UDP Port, and Field Replaceable Unit (FRU) status (like DC Current or Modem Board Temperature, depending on the model).
• Repeater Alarm Reporting detects and reports various hardware and environmental alarms, such as receiver/transmitter lock detect failure, AC power failure, overheating, VSWR detection, and software update management alarms.
• Repeater Control allows administrators to perform control operations, including changing the repeater's Enabled or Disabled status, changing channels, altering the Transmit Power Level (High or Low), and initiating a reset or knockdown of the repeater.

RDAC can be configured to connect to repeaters via an IP Network; locally via USB or via MOTOTRBO Link. However, in MOTOTRBO Link configurations, RDAC does support remotely monitoring the presence and alarm status of backhaul chain repeaters but remote control commands are not supported. In Dynamic Mixed Mode (DMM), RDAC over the network is not supported, but local USB monitoring is possible.

RDS

The Repeater Diagnostics System (RDS) feature is designed to enhance diagnostic capabilities providing several services used for syytem monitoring. These include:

• Software Alarm Detection and Control: RDS enables the ability to detect, report, retrieve, and clear various software alarms. It also allows for repeater software alarm control and configuration of automatic polling intervals.
• Logging and Management: When RDS is enabled, the repeater records internal logs, such as repeater field running logs and repeater Air tracer logs, usually to flash memory. The alarm information from multiple repeaters within the same system is stored in a common log file by the RDAC application, which includes a PC time stamp and the repeater peer ID. Logs for SLR Repeaters can be downloaded via the repeater's webpage.
• Connectivity: All RDS services are available when connecting via an IP network or locally through a USB.

Examples of Alarms Detected by RDS include informsation from the:

• OTA Layer: Alarms such as Color code failure, FCC interference type I and II, and MFID failure.
• IP Layer: Alarms related to link status between repeaters and call streaming failure.
• Network Layer: Alarms covering network cable errors, DHCP errors, and Gateway errors.

Reg

The term Reg primarily refers to a Registration flag or information element within the Digital Mobile Radio (DMR) Tier 3 trunking protocol and related standards.

REGI

The abbreviation REGI stands for Registration in the context of Digital Mobile Radio (DMR) Tier 3 trunking protocols.

Reg_Dereg

The information element Reg_Dereg is used in a radio Registration Service Request PDU to indicate whether it is attempting to register or de-register its location within a Tier 3 trunking system. The value and purpose of the Reg_Dereg information element depends on the state of the accompanying IP_Inform information element in the registration request.

Reg_Window

The term Reg_Window refers to an information element used in the DMR Tier 3 trunking protocol to manage Mass Reregistration procedures. This is broadcast by the control channel (TSCC) via the C_BCAST (Announcement_type = MassReg) PDU when the network needs many radios to re-register. Since a large number of radios, attempting to access the network simultaneously would cause congestion, the Reg_Window is designed to mitigate this issue by distributing the registration attempts over an extended period of time.

RFC

Request For Comments.

RSSI

RSSI stands for Received Signal Strength Indication. It is a metric used in MOTOTRBO systems, particularly in relation to channel access, roaming, and diagnostics. It is measured and presented in dBmV.

See RSSI Threshold.

R_1_2_DATA

The Rate ½ coded packet Data (PDU) is used to carry user data for both confirmed and unconfirmed data delivery within a packet when rate ½ coding is applied to the data blocks. When used for confirmed data, it has a length of 96 bits and includes fields for the Data Block Serial Number (DBSN) and C-DATA Cyclic Redundancy Checksum (CRC-9); when used for unconfirmed data, it uses all 96 bits for User Data.

R_1_2_LDATA

The Rate ½ coded Last Data block PDU is specifically the last data block in a packet when ½ rate coding is used. For unconfirmed data delivery, this 96-bit PDU carries 64 bits of User Data followed by a 32-bit Message CRC for error checking the entire data message. For confirmed data delivery, this PDU contains the Data Block Serial Number (DBSN), C-DATA CRC, 48 bits of User Data, and the 32-bit Message CRC.

R_HEAD

The Raw short data packet Header PDU is used for Raw short data delivery and has a length of 96 bits. Raw short data allows applications to manage the format of the transmitted data themselves.

R_Sync

Reverse channel Sync refers to the Synchronization (SYNC) pattern specifically used for the Reverse Channel (RC) burst. The RC burst is short, containing 96 bits in total, and the R_Sync pattern helps the receiver detect it and achieve bit synchronization.

S

S

S refers to the resynchronize flag, a single-bit information element used to resynchronize the physical sub-layer sequence numbers. When this flag is asserted (set to 1 ), the receiver should synchronize its sequence numbers with those in the header.

SA

SA either stands for Sync Age or System Advisor.

Sync Age

Sync Age is an 11-bit information element used in TDMA direct mode to indicate the time since the last beacon in increments of 500 ms. This value helps determine if received channel timing information is valid.

Capacity Max System Advisor

System Advisor

The System Advisor (SA) is an application designed to provide fault management, system, and call monitoring solutions for a Capacity Max system.

Its main purpose is to assist system maintainers by offering a centralized way to:

• Monitor the overall health of the radio system.
• View the status and alarms for infrastructure devices.
• Track call activity and channel usage within the system.

The server component of the System Advisor resides on the Capacity Max System Server (CMSS). Access to the System Advisor's information is achieved through a client application, which can be launched from a web browser that has an IP connection to the CMSS.

SAC

SAC stands for Subscriber Access Control. It is a data set within a Capacity Max system used for centralized management and restriction of services for all devices accessing the radio network. The primary function of the Subscriber Access Control is to control and maintain a list of permitted services and sites for every device (radios, voice logging applications, dispatch applications and data gateways) that accesses the system:

1. SAC is configured within the Radio Management (RM) application, and the information is primarily programmed into the Trunking Controller (TC).
2. When a radio sends a service request (e.g., attempting a call or registering), the system checks the SAC list. If the requested service or site is not permitted, the request may be denied.
3. SAC allows system administrators to make dynamic changes to the capabilities of a radio without reprogramming the radio,. This is useful for temporarily restricting services (e.g., due to non-payment of dues).
4. SAC records are integral to registration: if a radio is disabled in the SAC, it is not registered,. SAC also enhances security by supporting authentication mechanisms, especially when verifying the radio's unique Physical Serial Number (PSN).

SAC provides granular control over which services and sites are allowed for specific device IDs:

Type of Control	Examples of Restrictions
Service Initiation & Reception	Enabling/disabling the ability to initiate or receive Group Voice Calls, Individual Voice Calls, Emergency Calls, Broadcast Voice Calls, and Telephone Calls,,.
Command & Control	Enabling/disabling the ability to initiate or receive system commands like Remote Monitor, Radio Check, Stun/Revive, or Kill commands,,.
Site Access	Restricting the list of sites (Allowed Sites) where a specific radio is permitted to register, initiate, or receive a call,,.

All entities that act as endpoints for communication in the Capacity Max system require a unique entry in the SAC,:

• Motorola Radios: Automatically added to the SAC list upon system set selection,.
• Non-Motorola Radios, Consoles, and Data Gateways: Must be added manually to the SAC table,.

SACK

SACK stands for Selective ACKnowledgement. It is a response mechanism used in confirmed data transmission where the recipient requests the selective retry of specific corrupted blocks.

SAP

SAP stands for Service Access Point. The SAP Identifier (SAPID) is a 4-bit field in a data header used to identify the type of processing required for the subsequent data payload. Examples include IP based Packet data or Unified Data Transport (UDT).

SARQ

SARQ stands for Selective Automatic Repeat reQuest. It refers to the error control process used in confirmed data delivery. As a single-bit information element in short data, it specifies if the sender requires SARQ.

SC

SC stands for Send Correction. It refers to a procedure executed by a Mobile Station (MS) in TDMA direct mode when it detects that channel timing information needs to be corrected or propagated.

SDI

SDI stands for Source Dynamic Identifier. It is a 2-bit information element that is part of the TDMA direct mode Wide Area Timing Identifier (WATID). It characterizes a radios’ preference to serve as a timing leader (e.g., Low, Medium, or High preference).

SDL

SDL stands for Specification and Description Language. It is used in ETSI TS 102 361 to describe and illustrate system behavior and logical processes.

SDM

SDM stands for UDT Short Data Message. This is a data service used in DMR Tier 3 systems that allows data (up to 368 bits) to be transferred efficiently using the control channel.

SDMI

SDMI Stands for UDT Short Data Message Identity. This is a specific gateway address (FFFEC516) used in the DMR Tier 3 protocol to identify a UDT Short Data service.

SDU

SDU stands for Service Data Unit. It refers to the entirety of the data encapsulated within a Protocol Data Unit (PDU).

SEP

SEP stands for SEParation. It is an SDU Code relating to fixed channel plans, specifically defining the frequency separation (in kHz) between two adjacent channels.

SF

SF stands for Supplementary Flag. It is a 1-bit flag in the Unified Data Transport (UDT) Header. If set (12 ), it indicates the UDT is carrying supplementary data supporting another DMR Tier 3 service.

SFID

SFID stands for Standards Feature ID. It is a standardized 8-bit value (0000 0000₂) used to identify the default feature set containing the standard DMR services and facilities.

See also MFID.

SGI

SGI stands for Short Group Identity. It is a 15-bit portion of the Air Interface address space designated for group addresses.

SID

SID stands for Source IDentifier. It refers generically to the address of the transmitting entity.

SIMI

SIMI stands for Single Item Multi-Item data. It is a 1-bit flag in Packet Data Service requests used to indicate whether a session is for a Single Item Data transfer or a Multi-Item Data transfer.

SIP

See Session Initiation Protocol.

SITE

SITE is a parameter within the System Identity Code (C_SYScode) broadcast by the Trunk Station Control Channel (TSCC) used to identify a particular site within a network.

See also C_SYScode.

SLC

SLC stands for Short Link Control. It is a type of message structure designed to carry signaling within a small 28-bit information field, often transported via the Common Announcement Channel (CACH).

SLCO

SLCO stands for Short Link Control Opcode. It is a 4-bit information element that identifies the specific type of Short Link Control message.

SLOT

SLOT refers to timeslot. It is the elementary timing unit of the physical channel, lasting 30 ms.

Also the Slot Type PDU is a 20-bit field within data/control bursts that defines the purpose of the burst content.

SMS

SMS stands for Short Message Service. It is referenced in ETSI TS 102 361 as a service often handled through a gateway device, such as an SMS router.

SP

SP stands for Source Port. It is a 3-bit element specifying the source port number within certain packet headers.

SPID

SPID stands for UDP Source Port IDentifier. It is used in UDP/IPv4 header compression as an index to represent a preconfigured Source UDP port number.

SP_HEAD

SP_HEAD stands for Status/Precoded short data packet Header. It is a Protocol Data Unit (PDU) designed for Status/Precoded short data delivery where the message content is contained entirely within the header block.

SSI

SSI stands for Short Subscriber Identity. It is a 15-bit part of the Air Interface address that defines individual subscriber identities.

STDS

STDS stands for Supplementary Data Transfer Service. This service uses the Unified Data Transport (UDT) mechanism to transfer additional data (supplementary data) that supports or enhances a primary voice or data call setup.

STUNI

STUNI: Stands for MS Stun/Revive Identifier. This is a gateway address (FFFECC16) in DMR Tier 3 systems used to send signaling to a radio (MS) to deny (stun) or restore (revive) access to services.

SUPLI

SUPLI stands for Supplementary Data Identifier. This is a gateway address (FFFEC416) used to identify a supplementary data service within the Tier III protocol for transporting ancillary data.

SWATID

SWATID refers to the Source Wide Area Timing IDentifier, which is a component of the TDMA direct mode timing system.

SYNC

SYNC stands for SYNChronization. It refers to the special sequence of bits that marks the location of the center of a TDMA burst and is used by receivers for detection and synchronization.

SYS

SYS stands for SYStem. It forms part of the System Identity Code (C_SYScode), identifying the system and network identity.

See also C_SYScode.

SYS_AREA

SYS_AREA stands for System Area. It is an information element extracted from the SITE parameter of the System Identity Code by applying a mask. It is used in DMR Tier 3 registration procedures, particularly for maintaining a list of denied registrations.

See also C_SYScode.

T

TA

Talker Alias (TA) is an inband data service used during a voice call to provide alias information (like identifying text) of the transmitting radio to receiving radios. It can be a single or multi-packet data service.

TACT

TACT (TDMA Access Channel Type) is a 7-bit Protocol Data Unit (PDU) utilized for framing and status on the Common Announcement Channel (CACH) burst. It contains four information bits related to channel access and framing, which are protected by a Hamming (7,4) Forward Error Correction (FEC) code.

TATTSI

Talkgroup Subscription/Attachment Service (TATTSI) is a gateway address used to identify the service related to a radio informing the network about its talkgroup memberships. This address is utilized in registration requests when a radio attempts to subscribe or attach to a talkgroup list.

TC

TC (TDMA Channel) is a 1-bit information element in the Common Announcement Channel (CACH) PDU that indicates whether the subsequent inbound and outbound burst belongs to channel 1 or channel 2.

TCP

See Transmission Control Protocol.

TD

Terminator Data is referenced in the context of the Terminator Data Link Control (TD_LC) PDU. The TD_LC PDU is used to terminate a confirmed data transmission in direct mode and reserve the channel for the response.

TDD

See Time Division Duplex.

TDMA

Time Division Multiple Access is the fundamental method employed by DMR systems, which uses a 2-slot architecture within a 12.5 kHz Radio Frequency (RF) carrier bandwidth.

See also AI.

TD_GRANT

Talkgroup Data Channel Grant is a Control Signalling BlocK/Multi Block Control (CSBK/MBC) Protocol Data Unit (PDU) transmitted by the Trunk Station Control Channel (TSCC) to allocate a payload channel for a talkgroup data call in a DMR Tier 3 system.

TD_GRANT_MI

Talkgroup Data Channel Grant: Multi-Item is an opcode alias used for data calls destined for a talkgroup that involve transferring multiple data items.

TG

Talkgroup refers to a predetermined group of users that are addressed during a group call service.

TO

Time Out, specifically represented by the T_TO timer, limits the duration of a single transmission item. If this timer expires during a transmission, the Mobile Station (MS) ceases transmitting.

TOS

Type Of Service refers to the IPv4 Type Of Service information element, which is specifically not supported within the Radio Area Network (RAN) when utilizing UDP/IPv4 compressed headers.

TP

Timing Push is a procedure used in TDMA direct mode where a radio attempts to propagate or "push out" channel timing information to other units within the wide area system.

TP_Timer

TP_Timer is a Layer 3 timer that starts when a calling radio receives an acknowledgment following a service request for a call that requires a payload channel. The timer is typically reset upon reception of further call progress PDUs.

TRGT_ADR_CNTS

TRGT_ADR_CNTS (Target Address Contents) is a registration service information element used to specify the exact contents of the Target Address or Gateway information element during a registration request.

TRIBIT

A Tribit consists of 3 bits grouped together into a symbol. It is primarily relevant in the context of rate 3/4 Trellis encoding.

Trand_TC

Timeout for MS attempting Random Access is a timer defining the maximum overall time that a radio (or MS) will wait while attempting the random access procedure on the Trunk Station Control Channel (TSCC) before abandoning the process.

Trellis_Dibit

Output Dibit from Trellis Code (Trellis_Dibit) refers to the 2-bit output symbol (Dibit) generated by the Trellis encoder used during the rate 3/4 coding process.

TS

A Trunked Station (TS) [sometimes referrred to as a site controller] is the physical fixed-end equipment used to provide DMR Tier 3 services. It manages the control channel and allocates network resources. The TS for a Capacity Max system resides within the repeaters themselves, specifically the repeater currently the control channel (TSCC) host.

TSCC

A Trunk Station Control Channel [often just called a control channel] is the primary control channel transmitted by the infrastructure (TS) to manage and regulate the radio (MS) population, broadcast system parameters, and coordinate access.

TSCCAS

TSCCAS (Trunk Station Control Channel Alternate Slot) is a supplementary control channel that occupies the alternate timeslot when a physical channel supports both the TSCC and another function. It is frequently used for Unified Single Block Data (USBD) polling and data transfer.

TSI

Trunking Station Identifier is the address used to denote the Trunked Station (TS).

TV_GRANT

Talkgroup Voice Channel Grant is a Control Signalling BlocK/Multi Block Control (CSBK/MBC) PDU transmitted by the TSCC to transfer a talkgroup voice call to a designated payload channel.

U

UAB

UDT Appended Blocks is an information element contained within the Unified Data Transport (UDT) Header PDU and specifies the number of blocks appended to the header that contain data. It is typically a 2-bit field. In the context of IP connection advice, its value indicates whether the IPv4 or IPv6 address is being transmitted.

UDT

Unified Data Transport is a universal methodology used to transfer data packets (like Short Data or supplementary data) within DMR Tier III systems, often replacing multi-block Control Signalling BlocKs (CSBK),,. UDT packets consist of a header and one to four appended blocks transmitted consecutively.

UDTF

Unified Data Transport Format is a 4-bit information element that specifies the format of the data carried within the appended blocks of a multi-block UDT,,. This format determines the encoding type, such as Binary, BCD, text, or specific protocols like NMEA or Location Information Protocol (LIP).

UDTHD

The Unified Data Transport Header outbound PDU is used specifically on the outbound channel (control channel to radio). It is used to download UDT Supplementary Data or Short Data messages to a radio.

UDTHU

The Unified Data Transport Header inbound is specifically used on the inbound channel (radio to control channel). It is used by a radio to upload supplementary data or UDT Short Data messages to the system.

UDTO

UDT Opcode is a 6-bit information element found in the Unified Data Transport Header used to identify the operation or function of the UDT message.

UDP

User Datagram Protocol.

U-plane

The User plane is the part of the Data Link Layer (Layer 2) dedicated to transporting information without addressing capability, typically used for user voice services.

USB

Universal Serial Bus.

USBD

(Unified Single Block Data consists of a single block containing 10 octets of address/control information and data, followed by a 2-octet CRC. It is designed to support efficient data transfer mechanisms, notably in the USBD Polling Service used within Tier 3 trunking systems.

UTC

Universal Time Coordinated.

It serves as a time reference standard within DMR systems, particularly when broadcasting local time and date information via announcements.

• UTChh, UTCmm: These are elements used when broadcasting local time:
  • UTChh refers to the UTC time hours (00 to 23).
  • UTCmm refers to the UTC time minutes (00 to 59).
• UTCss3, UTCss6: These are elements related to UTC seconds used in NMEA data transmission formats:
  • UTCss3 refers to UTC time 10's seconds (a value in the range [0 to 5] multiplied by 10).
  • UTCss6 refers to UTC time seconds (00 to 59).

UTF

Unicode Transformation format (UTF) describes the character encoding standards used for carrying text data in DMR, including UTF-8, UTF-16, and UTF-32.

UTF-16BE

Unicode Transformation Format 16 bit Big-Endian refers to the Unicode Transformation Format 16 bit Big-Endian character encoding. It is specifically used for text messaging applications over the IP bearer service, commonly employed in the Basic Multilingual Plane.

UU

UU can refer to one of the following terms:

1. UU_Ans_Rsp (Unit to Unit Voice Service Answer Response) is the Unit to Unit Voice Service Answer Response Control Signalling BlocK (CSBK) PDU. It is used by the target radio) in an individual call (Off Air Call Set-Up method) to automatically respond, indicating whether the call is accepted or rejected.
2. UU_V_Ch_Usr (Unit to Unit Voice Channel User) is the Unit to Unit Voice Channel User Link Control (LC) PDU. This message is used for individual call service transmissions for purposes such as transmission addressing at initiation (Voice LC Header) and supporting late entry.
3. UU_V_Req (Unit to Unit Voice Service Request) is the Unit to Unit Voice Service Request CSBK PDU. It is transmitted by a source (calling) radio during the Off Air Call Set-Up (OACSU) method of an individual call to perform a presence check on the target (called) radio.

V

V+D

Voice and Data (Voice plus Data).

VN_AP

VN_AP (Vote Now Absolute Parameters) refers to a specific type of Appended MBC PDU (Multi Block Control Protocol Data Unit) used in DMR Tier 3 signalling. The VN_AP PDU serves as the second (continuation) block of the multi-block Vote Now MBC message. The overall Vote Now MBC message provides advice to idle radios (i.e. radios not in a call) to assess the signal quality of an adjacent Trunking System Control Channel (TSCC).

VS

VS (Vocoder Socket) is a term used to describe vocoder payload bits found within a voice burst structure. These vocoder bits are carried in a voice burst. Each voice burst provides a "vocoder socket" intended to carry 2 x 108 bits of compressed speech, which corresponds to 60 ms of speech. The vocoder bits are labelled VS0 to VS215.

When multiple vocoder frames (VF) are transmitted in the same burst, the order of these frames means that the Most Significant Bit (MSB) of the first frame (VF1) is transmitted as VS215, and the Least Significant Bit (LSB) of the last frame (VFM) is transmitted as VS0. Additionally, all bits of a given voice frame are placed contiguously within the burst.

VOTE_BLK

Vote Block (VOTE_BLK) defines a duration of time measured in TDMA frames (ranging from 2 to 10) during which a Trunking System Control Channel (TSCC) withdraws random access activity after a Vote Now Advice. The value for VOTE_BLK ranges from 2 to 10 TDMA frames.

V_Sync

TDMA Voice burst Sync (V_Sync) is the specific Frame Synchronization (SYNC) pattern used in TDMA (Time Division Multiple Access) voice bursts. Synchronization (SYNC) patterns generally consist of a special sequence of bits that mark the location of the centre of a TDMA burst. The primary function of using different SYNC patterns, like V_Sync, is to allow the receiver to differentiate voice bursts from data/control bursts and from Reverse Channel (RC) bursts.

Voice transmission utilizes a six-burst, 360ms superframe (designated A through F). V_Sync occurs only in Burst A (the first burst) of every voice superframe, marking the start of the superframe. Periodically inserting these voice syncs (V_Sync) allows late entry receivers to acquire synchronization and pick up voice messages after the transmission has already started. When a voice transmission is terminated, the burst immediately following the end of a voice superframe contains a data SYNC pattern instead of a voice SYNC pattern (V_Sync) to signal the termination.

V_Sync is a 48-bit SYNC pattern. The V_Sync bits occupy the center 48-bit field of the voice burst structure, placed between the two 108-bit vocoder payload fields (VS). It is distinct from the general Data burst Sync (D_Sync).

W

WACK

WACK primarily refers to a type of Wait ACKnowledgement within DMR Tier 3 trunking systems, such as MOTOTRBO Capacity Max. It is often seen as C_WACKD, which stands for a Wait ACKnowledgement outbound PDU (Protocol Data Unit).

WACKD

See WACK.

WD

WD (WithDrawn) is used in relation to the Trunked Station Control Channel (TSCC) and its management of channel access. It signifies that a particular communication channel or timeslot has been temporarily taken out of general availability for random access to ensure efficient and collision-free signalling for other, often solicited, transmissions.

WU

WU refers to Wakeup. Specifically, it is related to Wakeup Messages and associated timers and thresholds that a radio uses when attempting to activate a Base Station (BS) outbound channel or synchronize with it. Specifically, it refers to the system's mechanism for a radio to initiate contact and activate a base station when it cannot immediately detect or synchronize with the network's outbound signal.