Operating Manual Part 15

October 2008 5300 ES Series Mobile Radio Operating Manual 5-15
Conventional Features
5.13 Project 25 Mode Features
The following features are unique to conventional P25 channels.
5.13.1 Digital Unit ID
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.
5.13.2 Talk Group ID
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.
5.13.3 Network Access Code (NAC)
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.
5.13.4 P25 Group Calls
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.