Garmin Apollo SL40 Installation Manual page 36

Serial Data Specifications
a......... transceiver status:
R = normal receive
M = monitor selected
T = transmit enabled
S = stuck mic
s ......... squelch test setting:
0 = automatic
1 = test selected
Example Message
$PMRRC01G4LFR0F0<cr>
The active frequency is 119.100 MHz, the standby frequency is 124.550 MHz, normal
receive function, automatic squelch selected.
This message is output once/second.
S V
OFTWARE ERSION
This message is used to output the com software version.
Message Format
$PMRRC03vvvv<chksum><cr>
03....... message id
vvvv... software version
Example Message
$PMRRC03010024<cr>
The software version is 01.00.
This message is output once at power up and by request.
30 Apollo SL40 Installation Manual