190-01115-01
G3X/G3X Touch Installation Manual - RS-232 Text Output Format
Rev. AC
Page B-1
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
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).
