Group and Individual calls

Talk Group calls

Connecting to a talk group is done by pressing on the DDI slot shortcut associated to the talk group.  

Group calls can be handled either on the monitor applet, or on handsets.

Group calls are handled differently depending on the conversation mode. Differences for the turret user are small, but it's important to know which conversation mode is in use for the resources allocation on the radio system.

Per-Over : The session persists for the duration of a single speech over (PTT). This provides a transmission trunking call model.

When a turret user activates the microphone (on the monitor applet or on the handset) :

1.The TPO opens a session to the DMR AIS node.

2.When the session is established, a Push-To-Talk (PTT) request is sent.

3.When the PTT request is granted, the turret user can speak.

When someone else wants to speak on the group, the TPO receives an incoming session.  

•If no turret user monitors the talk group : the call rings like a normal call. A turret user needs to answer the call.

•If at least one turret user monitors the talk group : the session is automatically answered by the TPO. No action is required on the turret to listen to the talk group.

When the Push-To-Talk is released, the session is terminated.

Per-Conversation : The session persists for a period of time but may terminate eventually (for example on expiry of an inactivity timer). This provides a message trunking call model.

When a turret user activates the microphone (on the monitor applet or on the handset) :

•If there is no session between the TPO and the radio system:

1.The TPO opens a session to the DMR AIS node.

2.When the session is established, a PTT request is sent.

3.When the PTT request is granted, the turret user can speak.

•If there is already a session between the TPO and the DMR AIS node

1.A PTT request is sent.

2.When the PTT request is granted, the turret user can speak.

When someone else wants to speak on the group :

•If there is no session, the TPO receives an incoming call.  

oIf no turret user monitors the talk group : the call rings like a normal call. A turret user needs to answer the call.

oIf at least one turret user monitors the talk group : the session is automatically answered by the TPO. No action is required on the turret to listen to the talk group.

•If there is already a session, the TPO receives a notification that someone is speaking. (A session only remains if at least one turret user monitors the talk group).

When the Push-To-Talk is released, the session remains. The session terminates eventually on expiry of an inactivity timer.

Permanent : The session persists indefinitely. This provides an open channel call model.

The session is opened by the TPO when the place is started.

When a turret user activates the microphone (on the monitor applet or on the handset) :

1.A PTT request is sent.

2.When the PTT request is granted, the turret user can speak.

When someone else starts to speak on the group, the TPO receives a notification.

When the Push-To-Talk is released, the session remains.

The session terminates only when the place is stopped or when there is a problem between the TPO and the DMR AIS node.

Individual calls

Individual calls use the per-conversation mode.

Making an outgoing individual call is done by pressing an "Extension" shortcut with a specific extension prefix (see configuration).

Incoming individual calls ring like normal calls, turret user have to accept the call.

A free slot (not associated to a talk group and not currently in use) is allocated each time an incoming/outgoing individual radio call appears.

Identity of the dispatcher line linked to the DMR AIS place is used to handle these calls (incoming and outgoing).

Individual calls can be handled either on the monitor applet, or on handsets.