Appendix B Rs-232 Text Output Format - Garmin G3X Installation Manual

APPENDIX B RS-232 TEXT OUTPUT FORMAT

This data is output from a GDU 37X/4XX RX-232 port that has been configured to the "Text Out" format.
B.1 Electrical Interface
The output signals are compatible with RS-232C. Data is generated at 115,200 baud with a word length of
8 bits, one stop bit, and no parity.
B.2 Message Output Selection
Individual text output messages may be enabled or disabled in configuration mode. Enabling or disabling a
particular text output message has no effect on other text output messages.
B.3 General Message Output Format
Most text output messages have the following general format:
• Escape character ('=' symbol, 0x3D hex)
• ID character
• Version character
• Data characters (length determined by message ID)
• Checksum - 2-character (1-byte) ASCII hex value that is the simple sum of all previous
bytes, including the escape character
• Carriage return (0x0D hex)
• Line feed (0x0A hex)
An exception to the above is the GPS Data message, which is backwards compatible with the Garmin
Simple Text Output format described at:http://www8.garmin.com/support/text_out.html. The GPS Data
Message has the following general format:
• Escape character ('@' symbol, 0x40 hex)
• Data characters
• Carriage return (0x0D hex)
• Line feed (0x0A hex)
All text output messages use only printable ASCII characters. For all messages, a value that is out of range,
missing, not configured, uncalibrated, or otherwise invalid is indicated by replacing the corresponding
bytes within the message with the underscore character ('_', 0x5F hex).
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G3X/G3X Touch Installation Manual - RS-232 Text Output Format
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