What this is: a standards-based model of how a P25 trunked system sets up a group call — affiliation, control-channel request, channel grant, talk path, teardown. It is a learning simulator, not Motorola core software; no real provisioning UI, alarm codes, or service procedures are reproduced. Fire a PTT and watch the signaling move.

Control channel (always on) Signaling / grant Active talk path
ZONE CORE RF SITE SUBSCRIBERS Zone Controller channel grants UEM / UCS affiliation table GTR 8000 base / repeater CC + 0 traffic RF RID 1001 idle RID 1002 idle RID 1003 idle RID 1004 idle
SITE CHANNEL POOL

Call setup sequence

PTT
Affil
Req
Grant
Talk
End
A group call walks this path every time. When no traffic channel is free, the request is queued or busied instead of granted.

Controls

Tap a radio's PTT to originate a call to its talkgroup. Set channels to 1 and fire two different talkgroups to see queuing/busy behavior.

System state

Control channelC1 · broadcasting
Traffic free / total2 / 2
Active calls0
Queued0
Grants / Busies0 / 0

Event log