User's Manual

72
Channel Guard
Channel Guard encode is transmitted on analog clear channels only. Channel
Guard decode will operate on either a clear or private channel. The exception
is when G-STAR signaling is used (see G-STAR paragraph).
G-STAR
When G-STAR is programmed on a private channel, the radio will transmit G-
STAR in clear mode and then switch to private for the voice portion of the
call. If G-STAR is sent with Channel Guard, then both are sent in clear mode
and the radio switches to private mode. Emergency G-STAR data burst is
transmitted in clear mode.
DUAL CONTROL OPERATION
The M7100
IP
Series mobile radio can be programmed to operate from two
separate Control Units. This permits radio operation from two separate
locations in the vehicle. Dual control operation is available in both trunked
and conventional modes. Only one control unit can control the mobile radio
unit at a time. The control unit that controls the radio operation is called the
active controller and the second unit is called the idle controller.
Switching Control
Control can be switched to the idle controller by pressing the push-to-talk
(PTT) on the microphone associated with the idle controller. Once PTT is
pressed, the radio will switch control to the idle controller unless the active
controller is currently transmitting (i.e., PTT pressed on active controller), in
which case the switch will not occur. When control is switched to the idle
controller, two short high-pitched tones will sound at the controller where
PTT was pressed to indicate that the idle controller is now the active controller
and the previous active controller is now the idle controller.
Control Switching Modes
The radio can be pre-programmed for two modes of dual operation, “Slave”
and Independent. In the “Slave” mode, the two controllers will use the same
radio System and Group settings. The Independent mode permits each
controller to have its own saved System and Group settings.
Slave Mode Operation
In “Slave” mode, either controller can operate the radio with no change in
System and Group settings when control is switched. Both controllers display
the current information. If a key is pressed at the idle controller, other than
PTT,
E or siren and light keys as noted in following paragraphs, a low tone
will sound and the display will temporarily show DUAL on line 1 of the idle
controller.