190-01499-02
GTX 3X5 Transponder TSO Installation Manual
Rev. 4
Page 5-6
5.3
Power
The GTX 3X5 is compatible with 14 VDC and 28 VDC aircraft electrical systems. The AIRCRAFT
POWER 2 input is diode-isolated from AIRCRAFT POWER 1 and is used for connecting to an alternate
power source, such as on an aircraft with two electrical buses.
Table 5-3 Power Pins
Notes:
[1] Applicable to the GTX 335 and GTX 345 with internal GPS only.
The SWITCHED POWER OUT pin is a switched power output source, typically used for powering
devices such as a remote altitude encoder module. It is active when the GTX 3X5 power is on, and has a 1
ampere max rating.
On models with built-in GPS/SBAS, the GPS KEEP ALIVE input requires continuous battery power. This
battery input maintains the internal GPS clock and decreases initial GPS satellite acquisition time during
system power-up.
5.3.1
Power Configuration and Control Inputs
The power control inputs are for remote power on/off and enabling the power auto on feature.
The POWER CONFIG input controls the remote on/off feature. The POWER CONFIG input connects to
ground for remote unit installation. The input is left open for panel mount unit installation.
The POWER CONTROL connection controls the POWER CONTROL input. This is used as a remote
power on/off control or to use the power auto on feature when the avionics master is turned on.
Table 5-4 Power Configuration and Control Inputs
Pin Name
Connector
Pin
I/O
AIRCRAFT POWER 1
P3251
21
I
AIRCRAFT POWER 1
P3251
42
I
AIRCRAFT POWER 2
P3251
61
I
AIRCRAFT POWER 2
P3251
62
I
AIRCRAFT GROUND
P3251
20
--
AIRCRAFT GROUND
P3251
41
--
SWITCHED POWER OUT
P3251
39
O
GPS KEEP ALIVE [1]
P3251
60
I
Pin Name
Connector
Pin
I/O
POWER CONFIG
P3251
59
I
POWER CONTROL
P3251
38
I