MOTOTRBO Voice Call Features

One of the advantages of moving from analogue to DMR, is the ability to support many voice call types - beyond just an open channel for everyone. Although it was possible to use selective calling on an analogue conventional system, it was sometimes possible for other users, not party to that call, to listen in. A trunking system could be used but much of the equipment used in conjunction with such systems is (way beyond) end of life.

Here is a short overview of what voice call types MOTOTRBO Supports. These features are available on all system topologies, unless otherwise stated.

Private Call

With private call only the two blue radios are party to the call.

Sometimes called Individual Call, this is a call between two radios (or a radio and dispatch console). As the name suggests, only the called and calling radios are party to the call - all other users on the same channel cannot listen in.

While a private call is in progress on a conventional radio system, the channel (timeslot) will show up as busy to other users. On a trunked system, other calls can go ahead as normal since the channel used for calls is automatically assigned by the system.

On trunked systems like Capacity Plus or Capacity Max; if all voice channels are consumed at a RF site (i.e. all channels are busy with other calls), users wishing to make a call will either get a busy or their call will be placed into a queue. Capacity Plus does not support call queueing whereas Capacity Max does.

Group Call

This talkgroup call is between the green radios. Other radios on the same channel do not hear anything even if they are on the same channel. 

Sometimes called Talkgroup Call, a group call is a two-way call between any number of radio users -and, potentially, a dispatch console. A radio or console can be a member of more than one group - though on a radio, it is not possible to monitor more than one group at a time on a radio.

A Console can monitor more talkgroups at once but personally I don't like this idea if the other talkgroup is just as busy. Why? Its been scientifically proven that humans have a single speech processor and therefore cannot effectively listen to more than one conversation at a time.

As with other types of call, on trunked systems, users will either get a busy (Cap+) or call queue (CapMax) if all channels at the site are busy.

All Call

The purple radio makes an All Call to the yellow radios, even though they are in different talkgroups, they all (yellow) hear the transmission from purple but cannot respond.

All Call is a one-way call to all radios.

On a conventional system (Single Site and IP Site Connect) , the call will be received by radios on the same logical channel (same frequency + timeslot) irrespetive of which talkgroup the radios are on.

On a Capacity Plus system, All Call will go out to all idle radios on the system (i.e. radio which are not transmitting or receiving another call). To ensure calls made using All Call, are relevant and system users will pay attention, this functionality most only be given to users who will use it sparingly and responsibly (usually just the dispatchers). Also, to ensure, radio users don't miss these types of calls, it should ideally be used with Transmit Interrupt.

All Call also goes out to radio users who are not party to any talkgroup: on the systems I've helped build, I've often added a "standby channel". This is a channel/personality on the radio that the user can select when they are on standby at home; or are in a meeting and can do without the radio chatter. This channel is simply a channel without any RX Group List and TX Contact. When on this channel, the radio only responds to Private Calls and All Call.

Emergency Call

The top button is favoured for use as the emergency button.

MOTOTRBO radios allow the user to initiate an emergency call, either by pressing a preprogrammed emergency button (usually the orange one on the top); by failing to respond to the lone worker alert or by triggering a mandown event.

They would only initiate the emergency call if they were injured or their life was in danger. When triggering emergency, the radio con be configured to do certain things such as:

- Use Transmit Interrupt.
- Change to a difference (special) channel.
- Disable all alerts and lights.
- Appear to be turned off.
- Use higher microphone gain when transmitting.
- Automatically PTT every few seconds.
- Turn on the ability to respond to Remote Monitor (which would otherwise be disabled).
- Produce an emergency search tone.

- Send its location (if available).

In addition to the above, when transmitting, all radios monitoring that call will give a visual and audible indication that an emergency call has been (or is being) received.

On a mobile radio you would configure one of the front buttons for emergency. It's also possible to connect an external emergency momentary switch to do this.

On both the portable and mobile, the button can be configured with a delay so as to prevent accidental activation of emergency.

Lone Worker

Lone Worker is a feature that has been around on Motorola radios since the early 1990s. When enabled, a radio will operate normally. After a certain amount of time, the radio will sound a continuous alert. The user must respond to this alert by pressing any button on the radio. Doing so will reset the timer and the radio will continue to operate as normal until the alert comes up once again.

If the user fails to respond to this alert within a certain amount of time, the radio will trigger an Emergency Call (since the user is possibly in some sort of distress).

Mandown

Certain MOTOTRBO portables have a built-in Mandown option board. The mandown board can be used to trigger an Emergency Call if the radio is either tilted beyond a certain angle or is not moved for a certain amount of time.

On a Capacity Max system, Call Priority Level 1 is automatically assigned to any Emergency Call. This means that the users call; can potentially tear down another lower priority call, if the system is busy.

On a Capacity Plus system, you would probably want to use Transmit Interrupt with Emergency Call. This ensures that a logical channel is always freed up to pass the call.

OVCM Call (Conventional)

The purple radio has OVCM TX enabled and the blue radio has OVCM RX enabled - the result is that whenever the purple radio makes a group call to the green group, the blue radio can hear its (purple) transmission even tough it (blue) is not a member of the green talkgroup.

Open Voice Channel Mode (OVCM) is a feature that allows radios which are not normally part of a talkgroup call to either be party to a call; a transmission or to transmit to a talkgroup it is not a part of.

For example, if both OVCM TX  and RX are Enabled, the radio will make a call to its own talkgroup per the channel configuration and, at the same time will make a call OVCM call. This OVCM call will be received by radios; on the same logical channel with OVCM RX enabled.

If a radio has OVCM TX Enabled and OVCM RX Disabled it will initiate an OVCM call as a above but will not hear OVCM call made on the same logical channel unless the other radio is on the same talkgroup.  The user can reply to an OVCM call i n this case if they PTT within the repeater hang time.

More details about OVCM here.

Site Wide All Call and Multisite All Call (Capacity Max)

In a Capacity Max system, radios will always be affiliated (registred) on a specific site.

Capacity Max supports site-wide; multi-site and system wide All Calls. This means that a radio user can make a one-way voice call to all radio users on the same site; on multiple sites or to all radio users in the system.

When an All Call is made from a dispatch application, the destination site is included in the call setup.

As with regular talkgroups, the system administrator can configure the sites that are statically associated with the multi-site All Call group using the talkgroup Site Association setting in MOTOTRBO Radio Management. Talkgroup ID 1048416  to 1048543 is reserved for this purpose so they cannot be used for regular talkgroups.

For example (see the above diagram) if a yellow radio makes an All Call, it will go to all the yellow radios. If the same radio makes a Multisite All Call then this could be heard by blue and green radios - depending on how the system is set up. If the radio makes a System-wide All Call, then all the radios red, yellow, blue and green will hear the transmission.

The above is true for radios which are not involved in another call.

Telephone Call

A telephone system is connected to MOTOTRBO either via a Phone Patch or Application.

All MOTOTRBO systems, except Capacity Max support the ability to make and receive telephone calls via an external phone patch. The purpose of this feature is to support migration from analogue without the need to replace existing peripheral hardware such as a Phone Patch.

The Phone Patch is essentially an external device that acts as an interface between a POTS (FXO) line and repeater. In most cases, it also handles things like access codes and dial restrictions.

MOTOTRBO does not inherently support SIP but there are a number of 3rd party solutions that can act as a SIP client/aggregator as well as do the transcoding between AMBE+2 and G711 etc.

Capacity Max does not use a phone patch. If telephone interconnectivity is needed, a 3rd party solution should be used. This connects into the radio network via the MNIS VRC. The same method can be used to provide telephone interconnect on conventional and Capacity Plus systems.