E F Johnson Company 2425M70 Benutzerhandbuch

6-16

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 6.4 and the Monitor Mode described in 
Section 6.2.

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 6.2.

The radio can be programmed to provide an out of range indicator when used on an 
EFJohnson Infrastructure system. If the radio fails to receive the beacon signal from the 
system, then (if programmed) an out of range status will be indicated on the radio by a 
tone, display, or tone and display.