Connector Pinout Information
190-01499-02
GTX 3X5 Transponder TSO Installation Manual
Rev. 9
Page 5-8
5.5.2 Gray Code Altitude Input
The GTX 3X5 accepts ten Gray code altitude discrete inputs.
The Gray code inputs are pulled down for active, or open for inactive.
The GTX 3X5 includes internal isolation diodes on the Gray code inputs to prevent the unit from pulling the encoder
lines to ground when the transponder is turned off.
Table 5-7 Altitude Inputs
5.6
Discrete I/O
Active-Low discrete inputs are considered active if either the voltage to ground is <3.5 VDC or the resistance to ground
is <375 ohms. These inputs are considered inactive if the voltage to ground is 6.5-33 VDC or the resistance to ground
is >100 kilohm.
The GTX 3X5 has discrete outputs that are configurable. Each is an open drain output capable of sinking 250 milliamp
when active. For discrete input and output configuration refer to table 6-7 and table 6-8.
Table 5-8 Discrete Inputs and Outputs
Pin Name
Connector
Pin
I/O
ALTITUDE A1* or CONFIGURABLE*
P3251
10
I
ALTITUDE A2* or CONFIGURABLE*
P3251
32
I
ALTITUDE A4* or CONFIGURABLE*
P3251
53
I
ALTITUDE B1* or CONFIGURABLE*
P3251
11
I
ALTITUDE B2* or CONFIGURABLE*
P3251
33
I
ALTITUDE B4* or CONFIGURABLE*
P3251
54
I
ALTITUDE C1* or CONFIGURABLE*
P3251
12
I
ALTITUDE C2* or CONFIGURABLE*
P3251
34
I
ALTITUDE C4* or CONFIGURABLE*
P3251
55
I
ALTITUDE D4* or CONFIGURABLE*
P3251
13
I
ALTITUDE GROUND
P3251
56
O
Pin Name
Connector
Pin
I/O
EXTERNAL STANDBY SELECT* or CONFIGURABLE*
P3251
14
I
XPDR FAIL 1* or CONFIGURABLE*
P3251
17
O
EXTERNAL IDENT SELECT* or CONFIGURABLE*
P3251
36
I
AUDIO INHIBIT 2* or CONFIGURABLE*
P3251
37
I
SQUAT SWITCH* or CONFIGURABLE*
P3251
57
I
AIR DATA SELECT* or CONFIGURABLE*
P3251
58
I
CONFIGURABLE DISCRETE 1*
P3251
15
I/O
CONFIGURABLE DISCRETE 2 *
P3251
16
I/O
CONFIGURABLE DISCRETE 11*
P3252
13
I/O
CONFIGURABLE DISCRETE 12*
P3252
14
I/O
