Garmin GTX 3X5 Series Installation Manual - page 122

190-01499-02

GTX 3X5 Transponder TSO Installation Manual

Rev. 4

Page A-1

APPENDIX A

DATA FORMATS

A.1  RS-232 Air Data Input Format  .......................................................................................................A-1

A.1.1 Electrical 

Interface 

................................................................................................................ A-1

A.1.2  Altitude Format 1 Sentence  .................................................................................................. A-1

A.1.3  Altitude Format 3 Sentence  .................................................................................................. A-1

A.1.4  Airdata Format 1 Sentence  ................................................................................................... A-2

A.1

RS-232 Air Data Input Format

A.1.1 Electrical Interface

The input signals are compatible with RS-232C. Data input at 9600 baud with a word length of 8 bits, one 

stop bit, and no parity. One message is received per second.

A.1.2 Altitude Format 1 Sentence

The GTX 3X5 is capable of receiving the following 10-byte message from the altitude serializer.

ALT 12345

Where:

ALT

ASCII characters

space (0x20)

12345

altitude in feet

carriage return (0x0D)

A.1.3 Altitude Format 3 Sentence

The GTX 3X5 is capable of receiving the following 17-byte message from GAE modules, altitude 

serializers, and altitude converters.

RMS12345T12ul

Where:

RMS

ASCII characters

space (0x20)

sign indicator (0x2B[+] or 0x2D[-])

12345

altitude in feet

T

ASCII character

sign indicator

12

sensor temperature

ul

checksum of bytes 1 through 14 in hex ASCII (i.e., FA)

carriage return (0x0D)

NOTE

Checksum is calculated by adding each byte in the message (1 through 14).