Garmin GNC 420, Installation Manual, Page: 96 / 136

Page D-4 400 SERIES INSTALLATION MANUAL
Rev Q 190-00140-02
D.6.2 SHADIN “G” FORMAT
<STX>
GA012<CR><LF> "GA" (ASCII characters); "012" represents indicated Air Speed (knots)
GB345<CR><LF> "GB" (ASCII characters); "345" represents true Air Speed (knots)
GC678<CR><LF> "GC" (ASCII characters); "678" represents Mach Speed (thousandths)
GD<+/->9012<CR><LF> "GD" (ASCII characters); sign; "9012" represents pressure altitude (tens of feet)
GE<+/->3456<CR><LF> "GE" (ASCII characters); sign; "3456" represents density altitude (tens of feet)
GF<+/->78<CR><LF> "GF" (ASCII characters); sign; "78" represents outside air temperature (Celsius)
GG<+/->90<CR><LF> "GG" (ASCII characters); sign; "90" represents true air temperature (Celsius)
GH123<CR><LF> "GH" (ASCII characters); "123" represents wind direction (degrees from north)
GI456<CR><LF> "GI" (ASCII characters); "456" represents wind speed (knots)
GJ<+/->78<CR><LF> "GJ" (ASCII characters); sign; "78" represents rate of turn (degrees per second)
GK<+/->901<CR><LF> "GK" (ASCII characters); sign; "901" represents vertical speed (tens of ft/minute)
GL234<CR><LF> "GL" (ASCII characters); "234" represents heading (degrees from north)
GM5678<CR><LF> † "GM" (ASCII characters); "5678" represents fuel flow, right (Twin only) (tenths
gallons/hour)
GN90123<CR><LF> † "GN" (ASCII characters); "90123" represents fuel used, right (Twin only) (tenths
gallons)
GO4567<CR><LF> "GO" (ASCII characters); "4567" represents fuel flow, left (or Single) (tenths
gallons/hour)
GP89012<CR><LF> "GP" (ASCII characters); "89012" represents fuel used, left (or Single) (tenths gallons)
GQ001<CR><LF> "GQ" (ASCII characters); "001" represents error log/reason indicator (001 = temp. sensor
error, 000 = no errors)
GR6789.0<CR><LF> † "GR" (ASCII characters); "6789.0" represents fuel remaining (gallons)
Ga<+/->1234<CR><LF> "Ga" (ASCII characters); sign; "12.34" represents barometric corrected altitude (tens of
feet)
Gb56.78<CR><LF> "Gb" (ASCII characters); "56.78" represents current barometric pressure setting (inches
Hg)
G*901<CR><LF> "G*" (ASCII characters); "901" represents checksum
<ETX>
Where:
<STX> start-transmit character (0x02)
<CR> carriage-return character (0x0d)
<LF> line-feed character (0x0a)
<+/-> sign indicator (0x2b["+"] or 0x2d["-"])
<ETX> end-transmit character (0x03)
†
Not available from Airdata Computer
Note: Checksum is calculated by adding each byte in the message (including all characters from <STX>
up to and including the error log/reason indicator), such that carries are discarded to give a one byte result.
The ASCII-coded decimal representation of that byte is given, ranging from 0 (0x30, 0x30, 0x30) to 255
(0x32, 0x35, 0x35).