Serial altitude formats, Format 1, Format 2 – Dynon Avionics EFIS-D6 Installation Guide User Manual
Page 18: Format 3, Format 4

Instrument Installation
3-6
EFIS-D6 Installation Guide
SERIAL ALTITUDE FORMATS
There are four formats used by serial transponders. Choose the correct format for your
transponder in the ALTENC menu, using the FRMAT button.
Format 1
Used By
Dynon Encoder Serial-to-Gray Code Converter, Garmin
AT (formerly UPS Aviation Technologies)
Baud rate
1200
Format
#AL, space, +/-sign, five altitude bytes, T+25, checksum,
carriage return
Example message
#AL +05200T+25D7[CR]
Format 2
Used By
Magellan
Baud rate
1200
Format
$MGL, +/- sign, five altitude digits, T+25, checksum, carriage
return
Example message
$MGL+05200T+25E3[CR]
Format 3
Used By
Northstar, Garmin
Baud rate
2400
Format
ALT, space, five altitude bytes, carriage return
Example message
ALT 05200[CR]
Format 4
Used By
Garmin GTX327, GTX328, and GTX330 (set on Icarus
input), Icarus, Trimble
Baud rate
9600
Format
ALT, space, five altitude bytes, carriage return
Example message
ALT 05200[CR]