190-01499-02
GTX 3x5 TSO Installation Manual
Rev. 1
Page 5-9
5.8.3 HSDB
5.8.4 RS-422
The RS-422 interface conforms to the electrical specifications of EIA standard RS-422.
The RS-422 interface can be configured as an input or an output function depending on the installation.
See
section ___
.
5.9 Suppression Bus
The external SUPPRESSION BUS is intended for connection to other L-band equipment, such as a DME
or UAT. The SUPRRESION BUS 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 SUPPRESSION BUS is driven to
≥
18Vdc when the GTX 3x5 transmits. An input voltage of
≥
10Vdc
will suppress the GTX 3x5.
5.10 OAT Temperature Input
The GTX 3x5 includes an Outside Air Temperature (OAT) input, used for OAT and density altitude
displays.
The OAT input 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 1microamp per degree Kelvin (1uA/°K). Connect the
probe red wire to pin 25 and the black wire to pin 3.
Pin Name
Connector
Pin
I/O
HSDB 1 TX A
P3252
6
O
HDSB 1 TX B
P3252
1
O
HSDB 1 RX A
P3252
7
I
HSDB 1 RX B
P3252
2
I
HSDB 2 TX A
P3252
8
O
HDSB 2 TX B
P3252
3
O
HSDB 2 RX A
P3252
9
I
HSDB 2 RX B
P3252
4
I
Pin Name
Connector
Pin
I/O
RS-422 A
P3252
11
I/O
RS-422 B
P3252
12
I/O
Pin Name
Connector
Pin
I/O
SUPPRESSION BUS
P3251
18
I/O
Pin Name
Connector
Pin
I/O
OAT POWER
P3251
25
O
OAT INPUT
P3251
3
I
