Telephone Call Support in MOTOTRBO

All MOTOTRBO radios are able to make and receive telephone calls, either via a software appliance or via a hardware-based phone patch. Phone calls are, from the radio's side, semi-duplex - the radio user still needs to press PTT to speak and the telephone caller needs to wait for the radio user to finish talking (and releases the PTT) before replying.

In all cases, the radio is not connecting into the telephone network itself but rather via a repeater or backend network. This in turn is connected to a phone line or SIP exchange and provides telephone interconnectivity.

Radios without a display can only receive phone calls. Radios with a display but limited keypad can make phone calls to preprogrammed telephone numbers. Radios with a full-keypad can however, make phone calls to any number if such numbers are not barred on the system. The ION is currently not able to make phone calls over GSM and/or LTE.

In Single Site and IP Site Connect

There are two known methods for connecting a MOTOTRBO radio system into a phone systemː

• Via a Phone Patch
• Via a SIP Gateway

Digital Phone Patch

Digital Phone Patch was intended to allow a smooth migration to digital while allowing system owners to reuse their existing analogue phone patch hardware.

A basic diagram showing how an Analogue Phone Patch is connected to a SLR5500 to provide Digital Telephone Patch service.

To make a phone call, a radio user would make a call to the repeater and the radio would send the required DTMF tones. The repeater would present these tones to the analogue phone patch which in turn would place the call on the PABX or PSTN. The analogue phone patch would require a POTS line and would generally be connected to one of the repeaters via the accessory connector.

A CfS License is required to enable Digital Phone Patch functionality in the repeater.

Digital Phone Patch is supported in all MOTOTRBO hardware as of release 1.8 (launched sometime around 2010). Older hardware can be upgraded via CPS to firmware version R01.08.00 or later. to support this.

Digital Phone Patch does not support the following:

• Talkgroup to Phone Call . However, it is possible to call a Talkgroup from a phone.
• Caller Line ID or Phone Number presented to Radio User
• Phone Call Log in Radio (Missed, Answered, Outgoing)
• Radio System Logging of Dialed or Source Phone Number though this can be monitored at a PBX-level.
• Voice Prompts for Radio Users. Some Analogue Phone Patches did
• Custom Ring Tones
• No Transmit Interrupt of a Phone Call
• Encryption on Digital Phone Patch calls.
• Priority Sampling while in a Phone Call
• Emergency Phone Call. But, a radio can Emergency Revert out of a Phone Call.

Configuration

All MOTOTRBO repeaters are capable of supporting telephone interconnect through several models of Analogue Phone Patches.

The Zetron Model 30 Phone Patch, for example, interconnects via the repeater and allows users to initiate and receive land line telephone calls through a connected POTS line. When properly configured, radio users can initiate and answer telephone calls. Through selective signaling, calls from phone callers can be directed to any subscriber or to a specific user. Additionally, access control is also afforded by the Zetron Model 30 Phone Patch.

The connection between a SLR5500 and the phone patch requires a bespoke multi-core shielded cable between the D25 AUX connector on the repeater and screw-terminal block on the Zetron Model 30 Phone Patch. This cable provides the following inputs and outputs to the repeater. The pin numbering is that of a SLR5500 - for a complete listing of SLR5500 pinouts, see the SLR5500 page.

Pin	Function	Configuration	Note
	Transmit Audio	None	300mV nominal, Z=600Ω
	Receive Audio	None	80mV nominal, Z=2kΩ
	PTT	GPIO1, active low	When configured as an input an internal tie-up resistor is in place to sense the line being pulled to ground.
	COR	GPIO1, active high	When configured as an output, an open collector output is presented.
	13,6VDC	None	The SLR5500 provides a 13,6V output on the AUX connector but cannot be safely loaded with more than 1A
	Ground	None

Dialing Radios and Talkgroups via an Analogue Phone Patch

To make a private call to a radio, or a Talkgroup call to multiple radios, a phone caller will need to firstly dial the number associated with the phone patch. If not busy, the phone patch will answer the call and prompt the caller to dial a series of digits. These digits would be presented to and decoded by the repeater which will in turn make the necessary call to the radio(s).

To make a call to a radio with ID 501 on timeslot 1 of a conventional system, the caller would have to dial:

061269576826P18501

Where 061269576826 is the phone number of the Analogue Phone Patch. P usually inserts a 500ms pause between the two adjacent digits. Some phones will use a comma (,) instead of the P. The 1 after the P refers to timeslot 1 on the system. 8 means a private call and 501 is the Radio ID of the called radio. To make a group call to Talkgroup 101 on timeslot 2, the phone caller would have to dial:

061269576826P27101

Here too 061269576826 is the phone number of the Analogue Phone Patch. P (or comma) inserts a 500ms pause. The 2 after the P refers to timeslot 2 on the system. 7 means a talkgroup call and 101 is the ID of the target talkgroup.

To increase the delay between dialing the telephone number and sending the call steering digits, more Ps or commas can be added.

The caller can also manually dial the talkgroup or radio ID. In some cases, the Analogue Phone Patch will prompt the caller to do so.

Dialing a telephone number from a radio

To make a phone call, the radio user will need to firstly dial the access code for the phone patch, pause to get the dial tone then dial the telephone number:

1234#P061269576826

Here 1234# is the access code, P inserts a pause and 061269576826 is the telephone number. In order to make a phone call, the radio user needs to be on the same timeslot as the phone patch.

SIP Gateway

If a SIP gateway is used, this would typically be connected to the repeater via IP. Note that the repeater does not have a SIP client and cannot transcode between AMBE and G711.

In Capacity Plus and Multisite Capacity Plus

Dialing Radios and Talkgroups via an Analogue Phone Patch

To make a private call to a radio, or a Talkgroup call to multiple radios, a phone caller will need to firstly dial the number associated with the phone patch. If not busy, the phone patch will answer the call and prompt the caller to dial a series of digits. These digits would be presented to and decoded by the repeater which will in turn make the necessary call to the radio(s).

To make a call to a radio with ID 501 in a Capacity Plus system, the caller would have to dial:

061269576826P8501

Where 061269576826 is the phone number of the Analogue Phone Patch. P usually inserts a 500ms pause between the two adjacent digits. Some phones will use a comma (,) instead of the P. The 8 after the P means a private call and 501 is the Radio ID of the called radio. To make a group call to Talkgroup 101, the phone caller would have to dial:

061269576826P7101

Here too 061269576826 is the phone number of the Analogue Phone Patch. P (or comma) inserts a 500ms pause. The 7 after the P means a talkgroup call and 101 is the ID of the target talkgroup.

To increase the delay between dialing the telephone number and sending the call steering digits, more Ps or commas can be added.

The caller can also manually dial the talkgroup or radio ID. In some cases, the Analogue Phone Patch will prompt the caller to do so.

SIP Gateway

If a SIP gateway is used, this would typically be connected to the repeater via IP. Note that the repeater does not have a SIP client and cannot transcode between AMBE and G711.

In Capacity Max

Capacity Max does not support Phone Patch like in IPSC and capacity Plus (above). Instead, phone calls are passed through the MNIS VRC Gateway and SIP Gateway or Dispatch Application.