Appendix C. 400 Series Rs-232 Aviation Data Format - Garmin GNC 420A Installation Manual

Appendix C. 400 Series RS-232 Aviation Data Format

C.1 ELECTRICAL INTERFACE
The output signals shall be compatible with RS-232C. Data shall be generated at 9600 baud with a word
length of 8 bits, one stop bit, and no parity.
C.2 GENERAL OUTPUT FORMAT
The 400 Series RS-232 data shall have the following general format:
STX - ASCII start-of-text character (02 hex)
t1s - Type 1 output sentences (see following paragraphs for description)
t2s - One or more type 2 output sentences (see following paragraphs for description)
ETX - ASCII end-of-text character (03 hex)
C.3 OUTPUT SENTENCE TYPE 1
The Type 1 output sentences shall have the following general format:
id - item designator (single ASCII alphabetic character)
dddd - item data (1 to 10 printable ASCII characters)
CR - ASCII carriage return character (0D hex)
LF - ASCII line feed character (0A hex)*
Each Type 1 sentence shall be output by the 400 Series unit approximately once every second.
The track, desired track, and bearing to waypoint angles, and the magnetic variation are output according
to the current mode of the 400 Series unit (automatic magnetic heading, magnetic variation computed at
last known position; true heading, magnetic variation of E00.0°; or user-defined magnetic heading,
magnetic variation as entered by user).
400 SERIES INSTALLATION MANUAL
P/N 190-00140-02
Page C-1
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