Connector Pinout Information
190-01499-02
GTX 3X5 Transponder TSO Installation Manual
Rev. 9
Page 5-7
5.4
Lighting Bus
The lighting bus input controls the front panel display and keypad brightness of panel mount units using the aircraft
panel lighting bus. The GTX 3X5 can also be configured to adjust the display and keypad brightness for ambient
lighting conditions using an internal photo sensor.
The lighting bus input is configured for 5 VDC, 14 VDC, 28 VDC, or 5 VAC inputs.
Use both the LIGHTING BUS HI and LIGHTING BUS LO inputs to connect the lighting bus input to a
5 VAC bus.
Use the LIGHTING BUS HI input to connect the light bus input to a DC input. The return is the unit ground connection.
LIGHTING BUS LO should be left open.
Table 5-6 Lighting Bus Pins
5.5
Altitude Inputs
The GTX 3X5 uses pressure altitude inputs from several different sources:
•
Gray code inputs
•
RS-232 serial inputs
•
ARINC 429 inputs
•
The optional GAE module (Garmin P/N 011-03080-00)
•
HSDB
For altitude source priorities refer to section 3.10. With the proper encoder, the Mode S transponder transmits altitude
reporting in 25-foot resolution to ground stations and other aircraft. The unit must receive altitude from an applicable
altitude reporting device or from the optional GAE module. A parallel Gray code encoder provides altitude in 100 foot
resolution.
For altitude encoders that supply both a serial interface and the parallel Gray code input, such as the
GAE 43 (P/N 013-00066-00), connect one or the other interfaces, but not both. The serial interface is preferred.
5.5.1 Pressure Sensor Module
The optional GAE module (Garmin P/N 011-03080-00) is used for the GTX 3X5 pressure altitude input. It uses the same
interface as the configuration module and also includes the configuration module functionality.
Pin Name
Connector
Pin
I/O
LIGHTING BUS HI
P3251
19
I
LIGHTING BUS LO
P3251
40
I
