Emergency Channel; Stuck Microphone - Garmin GPS 400W,GNC 420W Pilot's Manual & Reference

when finished.
4. Turn the large right knob to highlight the
desired frequency.
Press ENT to place the highlighted frequency
5.
in the standby COM window field.

Emergency Channel

The 420W/430W emergency channel select pro-
vides a quick method of selecting 121.500 MHz as the
active frequency in the event of an in-flight emergency.
The emergency channel select is available whenever
the unit is on, regardless of GPS or cursor status, or
loss of the display.
To quickly tune and activate 121.500, press and
hold the COM flip-flop key for approximately two
seconds.
Press and hold the COM flip-flop key for
two seconds to activate the 121.500 MHz
emergency frequency.
Note: Under some circumstances if the com sys-
tem loses communication with the main system,
the radio will automatically tune to 121.500
MHz for transmit and receive regardless of the
displayed frequency.
420W / 430W Only

Stuck Microphone

Whenever the 420W/430W is transmitting, a 'TX'
indication will appear in the COM window. If the
microphone is stuck or accidentally left in the keyed
position, or continues to transmit after the key is
released, the COM transmitter will automatically time
out (or cease transmitting) after 35 seconds of continu-
ous broadcasting. You'll also receive a "COM push-to-
talk key stuck" message as long as the stuck condition
exists.
A "COM push-to-talk key stuck" message
appears to warn you of a stuck microphone.
Transmitting is disabled after 35 seconds of
continuous broadcasting.
1 - COM
Emergency Channel
27