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The following features are unique to conventional P25 channels.

Each radio that operates on Project 25 (digital) channels is programmed with an up-to-
eight-digit unit ID. This ID is unique for each radio and can be any number from 1-
16,777,215. When power is turned on with a Project 25 channel selected, this ID is briefly 
displayed.

Each Project 25 channel is programmed with a group ID that determines which group of 
radios will receive the call. A call is received on a channel if a selected or scanned channel 
is programmed with that ID and the correct NAC is detected (see following). Group IDs 
can be any number from 1-65,535. Group ID detect can be disabled by the Normal/
Selective squelch function described in Section 5.4 and the Monitor Mode described in 
Section 5.2.

Project 25 conventional channels also use a NAC (Network Access Code) to control 
which calls are received on a channel. The NAC can be 1-4095, and each transmit and 
receive channel can be programmed for a different code. Other operation, such as 
monitoring before transmitting, is similar to that of analog channels. NAC (and group ID) 
detect can be disabled by the monitor mode described in Section 5.2.

P25 Group calls are placed by simply selecting the channel programmed for the desired 
group, monitoring the channel if required, and transmitting. When a P25 group call is 
received, the alias (or frequency) of the selected channel is displayed. The radio can be 
programmed so that the following are also displayed for 0.5-7.0 seconds or continuously 
during the call.

P25 PTT ID - The unit ID of the radio placing the call is displayed.

P25 Talk Group - The alias of the talk group on which the call is being received is 
displayed.