Garmin GTX 3X5 Series Installation Manual page 122

SHADIN S FORMAT
<STX>
SA012<CR><LF>
SB345<CR><LF>
SC678<CR><LF>
SD<+/->9012<CR><LF>
SE<+/->3456<CR><LF>
SF<+/->78<CR><LF>
SG<+/->90<CR><LF>
SK<+/->901<CR><LF>
SL234<CR><LF>
Sa<+/->1234<CR><LF>
Sb56.78<CR><LF>
S*901<CR><LF>
<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)
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).
190-01499-02
Rev. 9
SA (ASCII characters); 012 represents indicated air speed (knots)
SB (ASCII characters); 345 represents true air speed (knots)
SC (ASCII characters); 678 represents Mach speed (thousandths)
SD (ASCII characters); sign; 9012 represents pressure altitude (tens of feet)
SE (ASCII characters); sign; 3456 represents density altitude (tens of feet)
SF (ASCII characters); sign; 78 represents outside air temperature (Celsius)
SG (ASCII characters); sign; 90 represents true air temperature (Celsius)
SK (ASCII characters); sign; 901 represents vertical speed (tens of ft/minute)
SL (ASCII characters); 234 represents heading (degrees from north)
Sa (ASCII character); sign; 1234 represents barometric corrected altitude (tens of feet)
Sb (ASCII character); 56.78 represents current barometric pressure setting (inches Hg)
S* (ASCII character); 901 represents checksum
GTX 3X5 Transponder TSO Installation Manual
Data Formats
Page A-4