Revision A GTX 330-3
GRT Avionics Garmin GTX 330 Series Supplement
Section 1: Introduction
1.1 About the GTX 330 Series
The Garmin GTX 330 Mode S transponder series provides normal altitude encoding data to ATC
as well as traffic data link capability to the GRT family of EFIS systems. With the use of an ES
(Extended Squitter) version of the GTX 330 series, you have the first step to ADS-B compliance for
the 2020 mandate. This supplement provides suggested methods for connecting the GPS to the
EFIS display unit to allow optimal performance of both units.
Download the current installation manual appropriate for your transponder from the Garmin
website and follow all instructions thoroughly. GRT provides pin assignments here for convenience.
While the chance that pin assignments will change is very slim, Garmin may change them at any
time.
The interface between this unit and the EFIS allows for:
Ÿ
Pressure altitude, flight ID, GPS position, groundspeed and ground track to be transmitted to ATC
ground stations
Ÿ
TIS traffic alerts (both units) and ADS-B OUT (GTX 330ES only when paired with suitable GPS)
Ÿ
Note: In this section, wherever the term GTX 330 is used, it applies to either of the following
transponders: GTX 330, GTX 330ES.
1.2 Data Port & Hardware Requirements
NOTE: Serial setup is recommended for simplicity. Advanced users concerned about running out
of serial ports may utilize ARINC 429 instead of serial data. Refer to GTX 330 installation manual
for details. GRT Sport EFIS systems require the external GRT ARINC429 module for ARINC
connections. Horizon HX and HXr systems have built-in ARINC 429 ports (Connector C).
Required Display Unit Data Port
Suggested Assignment
Serial Port IN
Serial 2 IN
Serial Port OUT
Serial 2 OUT
