Automatic Registration Service

ARS (Automatic Registration Service) is a message type using by MOTORBO radios to indicate to an application that it is tuned on and within range of the radio system. It can be used in all system topologies except Capacity Max which has its own method for determining presence. A radio can be configured to automatically announce its presence to a computer-based application. The radio would typically be configured to send the ARS message, either when the user turns the radio on; when the user changes channel or the radio moves (roams) between repeater sites.

This allows an application to determine whether a radio user is on the air and which channel or site the radios is on. It saves applications, like Radio Management and IMPRES Battery Fleet Management, from having to check if radios are online before commencing with any tasks. Also, users don’t have to “report in” when starting their working day - the radio informs the dispatcher automatically.

ARS results in a small increase in system loading. An application is always needed to receive and process these ARS messages. Portable radios will consume a little bit more energy so system designers may need consider higher capacity batteries or account for additional battery discharge when designing the system.

It functions even in the absence of location data (i.e. no GPS signal) and on radios without GPS. This is a digital only feature and available on all MOTOTRBO radios.

Note: if ARS is enabled in the radios, there must be a radio or application to receive this otherwise, all radios will endlessly retry thereby flooding the channel with traffic.

The TRBONET Dispatch and Location Tracking Application from Neocom. The user Brad Pitt is online (blue icon) whereas the user Chuck Norris is offline (grey icon).

System Specific Impementation

In Conventional and IP Site Connect Systems.

ARS messages can be sent on the currently selected channel or on a data revert channel. It is possible to use ARS on a simplex system but radios must be within RF range of the Control Station when powering on. In systems with at least one repeater, MNIS can be used instead of a Control Station.

Note: if ARS is enabled in the radios, there must be a radio or application to receive this otherwise, all radios will endlessly retry thereby flooding the channel with traffic.

In Capacity Plus

ARS messages can be sent either on the current rest channel or, if enhanced GPS is enabled, on a data revert channel, if one is available.

ARS Initialization Delay

Upon power on, subscribers normally register with the Presence Notifier by sending ARS messages immediately. In a scenario where a user has a system with many radios powering on within a short time, there can be many collisions between ARS registration messages. To reduce collisions, it is possible to configure the maximum value of an initial random delay for ARS registration through the CPS/RM. This field is called ARS Initialization Delay and has a range of 0 minutes to 4 hours with a default value of 0 minutes.

A value of 0 means that the ARS registration message is sent out 5-15 seconds from power on or site change. If one selects a value of 30 minutes, then the radio randomly chooses a time between 5 seconds and 30 minutes and sends the ARS when this random time elapses. This randomization of time between many radios sending ARS reduces collisions at power on.

ARS Registration on Roaming

When a radio with data capabilities and ARS enabled roams, it can be configured to automatically send ARS registration messages to the Presence Notifier (i.e. dispatch) application. This ARS registration on roaming capability can be enabled or disabled through CPS/RM configuration, and is applicable in both Passive Site Search and Active Site Search.

During Passive Site Search roaming, when ARS registration on roaming is disabled, the radio roams when the RSSI of the repeater roamed into is greater than the RSSI of the current Home channel by 0dB. However, when ARS registration on roaming is enabled, the radio roams only when the RSSI of the repeater roamed into is greater than the RSSI of the current Home channel by 6 dB. As a result, this reduces frequent registrations on roaming.

During Active Site Search roaming, when ARS registration on roaming is enabled, the radio automatically sends an ARS message to the Presence Notifier application if it roams into a site successfully. This ARS registration on roaming capability can be used by user applications to monitor which repeater site a radio is currently in.

System Requirements

In general, there needs to be a radio channel (i.e. frequency pair + slot) to carry the ARS message. The channel can be a rest channel on a Capacity Plus system; a channel on an IP Site Connect system or simply a simplex channel. In these systems (i.e. everything except Capacity Max), ARS messages are directed to the Motorola DDMS middleware hosted on a PC somewhere in the system. The DDMS application determines which radio is active and on which slot/site.

If an application, that uses DDMS is used, there either needs to be a Control Station connected to the PC or the PC needs to be connected to a repeater and the repeater(s) on which ARS will be sent, need(s) to have the NAI Data licence activated.