Garmin GNC 255 Installation Manual - page 92
GTR 225/GNC 255 TSO Installation Manual
190-01182-02
Page B-12
Rev. B
B.2.4.2 Output Messages
B.2.4.2.1 COM Transceiver Status
This message is used to output the current status of the GTR/GNC COM. It will be output at the
configured message rate (1 Hz) or whenever the status changes.
Message format:
“C” ..........................Message class. This is a GTR/GNC COM message.
“01”.........................Message identifier.
mk ...........................Active frequency: m = MHz, where m = desired MHz frequency - 30h,
ranging from 118 to 136 MHz, (i.e. 76h to 88h, A2h); k = (KHz offset /
25KHz) + 30h, ranging from 000 to 975KHz in 25 KHz steps.
mk ...........................Standby frequency: m = MHz, where m = desired MHz frequency - 30h,
ranging from 118 to 136 MHz, (i.e. 76h to 88h, A2h); k = (KHz offset /
25KHz) + 30h, ranging from 000 to 975KHz in 25 KHz steps.
a...............................Transceiver status:
I = Intercom (no other status applicable)
R = Normal receive
M = Monitor receive
T = Transmit active
S = Stuck mic
F = Comm failure
s...............................Squelch setting: (ASCII) 0 = automatic; 1 = manual override (“SQ” shown in
upper-left corner of COM active frequency.)
hh ............................COM channel spacing: (ASCII) 25 = 25 KHz mode; 83 = 8.33 KHz mode.
o ..............................Active frequency 8.33 KHz offset: (ASCII) 0 = 25 KHz frequency (.000); 1 =
first 8.33 KHz channel offset (.005); 2 = second 8.33 KHz channel offset
(.010); 3 = third 8.33 KHz channel offset (.015).
o ..............................Standby frequency 8.33 KHz offset: (ASCII) 0 = 25 KHz frequency (.000); 1
= first 8.33 KHz channel offset (.005); 2 = second 8.33 KHz channel offset
(.010); 3 = third 8.33 KHz channel offset (.015)
Example message:
$PGRMC01G4LFR08303
Active frequency is 119.100MHz, the standby frequency is 124.565MHz, unit is receiving, squelch is
automatic, and the unit is in 8.33 KHz mode.
Note: This message is output at a nominal one second rate, or faster whenever the transceiver function or
status changes.