Garmin GTR 225 Installation Manual page 86

B.2.3 Message Output Rate
The GTR/GNC will output the following messages at the specified rates:

CDI, VDI, and Flags at 10Hz (high rate).
 Decoded OBS Setting at 10Hz (high rate).
 Radial from Active VOR at 10Hz (high rate).
 Decoded Station Identifier at 1Hz (low rate).
 NAV Receiver Status at 1Hz (low rate).
 COM Transceiver Status at 1Hz (low rate).
B.2.4 Message Definitions
B.2.4.1 Input Messages
B.2.4.1.1 Request Data Output
This input command is used to request an output message to be sent by the GTR/GNC. Message data may
be specified. There are a few important things to keep in mind:
 The GTR/GNC will flag the specified message for output when it receives the request. There will
be a lag between the time the message is flagged for output and the time it is actually output. If
another request for the same message is received in this period, then the previous request will be
lost. The amount of lag depends on the number of messages that are consecutively flagged for
output.
• Use of unsupported output identifiers will not generate a Communication Error message.
Message format (GNC NAV requests):
"V" ..........................Message class. This is a GNC NAV request.
"24".........................Message identifier.
ii ..............................Output identifier of requested message, two ASCII characters. 29 = Request
"000" .......................Reserved.
Message format (GTR/GNC COM requests):
"C" ..........................Message class. This is a GTR/GNC COM request.
"06".........................Message identifier.
ii ..............................Output identifier of requested message, two ASCII characters. 02 = Request
d ..............................Message sub-id; set to (ASCII) 1 for Request COM Audio Volume, 0
"00".........................Reserved.
GTR 225/GNC 255 TSO Installation Manual
Page B-6
NAV Audio. 40 = Request NAV Volume. 41 = Request GNC Status.
COM Audio Volume. 03 = Request COM software version. 13 = Request
GTR Status.
otherwise.
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Rev. B