Page A-72
G900X/G950 Installation and Maintenance Manual – Pinouts
Revision D
190-00719-00
A.7.5 Discrete
Function
Discrete functions with pin assignments are shown for reference since the functions are available in the
GTX 33. External suppression should be connected if another transponder or DME is installed in the
aircraft avionics system. Depending on system configuration, the G900X/G950 system may not use these
inputs, as many functions are received from the GIA 63W in RS-232 format.
A.7.5.1 Discrete Outputs
External suppression should be connected if a DME is installed in the aircraft avionics system. The
GTX 33 suppression I/O pulses may not be compatible with all models of DME. Known incompatible
units include the Bendix/King KN 62, KN 64 and KNS 80. These models have an output-only
suppression port and can be damaged by the GTX 33 mutual suppression output. In this case, leave the
suppression pin open.
Pin Name
Connector
Pin
I/O
ALTITUDE ALERT ANNUNCIATE*
P3301
19 Out
EXTERNAL SUPPRESSION I/O (TXP/DME)
P3301
31 I/O
SIGNAL GROUND
P3301
51 --
SIGNAL GROUND
P3301
58 --
*
INACTIVE: 10
≤
Vin
≤
33VDC or Rin
≥
100k
Ω
ACTIVE: Vin
≤
1.9VDC with
≥
75 uA sink current, or Rin
≤
375
Ω
Sink current is internally limited to 200 uA max for a grounded input
A.7.5.2 Discrete Inputs
Pin Name
Connector
Pin
I/O
EXTERNAL IDENT SELECT*
P3301
12 In
EXTERNAL STANDBY SELECT*
P3301
13 In
SQUAT SWITCH IN
P3301
17 In
TIS CONNECT SELECT*
P3301
46 In
AUDIO MUTE SELECT*
P3301
47 In
*
INACTIVE: 10
≤
Vin
≤
33VDC or Rin
≥
100k
Ω
ACTIVE: Vin
≤
1.9VDC with
≥
75 uA sink current, or Rin
≤
375
Ω
Sink current is internally limited to 200 uA max for a grounded input
EXTERNAL IDENT SELECT (remote IDENT) is a momentary input.
EXTERNAL STANDBY SELECT (remote STANDBY) is a momentary input used when two GTX 33
systems are installed in an aircraft. When EXTERNAL STANDBY SELECT is grounded, ARINC 429
OUT PORT 1 remains active, while PORT 2 is inactive.
When TIS is inactive, the GTX 33 logs onto TIS service when a momentary ground is applied to
P3301-46. When TIS is active, a momentary ground logs off of TIS service.
An AUDIO MUTE SELECT mute switch may be used to control TIS audio alerts. TIS (Traffic) Mute
must be clearly marked with MUTE ON/MUTE OFF or TIS Audio ON/Audio OFF labels. The muting
feature may be enabled through a Multi-Function display. In order to prevent inadvertent muting, the
status of muting must default to "Mute off" upon each power cycle.