Suppression Bus; Oat Input; Audio Output; Time Mark - Garmin GTX 3X5 Series Installation Manual

5.8

Suppression Bus

The EXTERNAL SUPPRESSION is intended for connection to other L-band equipment, such as a DME or UAT. The
output is active whenever the GTX 3X5 transmits. When driven by another source, the GTX 3X5 transponder receiver
and transmitter functions will be suppressed.
The EXTERNAL SUPPRESSION output is driven to > 18 VDC when the GTX 3X5 transmits. An input voltage of > 10 VDC
will suppress the GTX 3X5.
EXTERNAL SUPPRESSION
5.9

OAT Input

The GTX 3X5 includes an OAT input, used for OAT and density altitude displays.
TEMP PROBE IN uses a current sensor type probe, such as the EDMO P/N 655-PROBE or the Davtron
P/N C307PS. The temperature input specification is 1 microamp per degree Kelvin (1uA/°K). Connect the probe positive
wire to pin 25 and negative wire to pin 3. For wire designations refer to the manufacturer's specifications.
TEMP PROBE OUT
TEMP PROBE IN

5.10 Audio Output

The audio output is used to provide aural traffic alerts. The output is capable of 100 mW into a 500 ohm load.
AUDIO OUT HI
AUDIO OUT LO

5.11 Time Mark

TIME MARK A
TIME MARK B
With either a GTX 335 or GTX 345 with internal GPS, the TIME MARK can be used as an output to provide 1PPS to
other equipment in the aircraft.
190-01499-02
Rev. 9

Table 5-13 External Suppression Bus Pin

Pin Name

Table 5-14 OAT Input and Output

Pin Name

Table 5-15 Audio Inputs and Outputs

Pin Name

Table 5-16 Time Mark Outputs

Pin Name
Connector Pinout Information
Connector Pin
P3251 18
Connector Pin
P3251 25
P3251 3
Connector Pin
P3251 46
P3251 47
Connector Pin
P3251 4
P3251 26
GTX 3X5 Transponder TSO Installation Manual
I/O
I/O
I/O
O
I
I/O
O
O
I/O
O
O
Page 5-11