2 channel radio system - channel usage scheme - gospel according to zerg90

for any 2 channel public safety radio system - police or fire or ems -
trunked or conventional - with MDTs or without

channel 1 - home channel - dispatch and response and most ops - prime
channel - primary channel - main channel

channel 2 - low priority messages - long messages - fallback for ch 1
- 2ndary channel

everyone starts the shift on channel 1 and stays on channel 1 - UNLESS
- they have a low priority message or a long message or want a warrant
check etc - then they switch to channel 2 (no permission needed) -
there is always at least 1 dispatcher listening to ch1 and ch2

as always - dispatcher needs ability to talk over any field unit - as
always the dispatcher needs to be able to receive and transmit at the
same time ("duplex" operation) - as always the dispatchers need access
to instant audio playback so they can review any missed messages
quickly