190-01499-02
GTX 3X5 Transponder TSO Installation Manual
Rev. 4
Page 6-12
DISCRETE IN
Refer to section 5 for pinout information.
NOTE
The source priority is based upon the selections made during configuration. Refer to
section 3.10.
Table 6-7 Discrete Inputs
Figure 6-11 Discrete In Page
Function
Selection
Description
AUD MUTE
All discrete inputs
The audio output will be muted until the discrete is opened.
This is connected to a higher priority audio such as TAWS.
AUD CNCL
Off
P3251-37
When this discrete is grounded by a momentary switch, audio
alerts are canceled.
IDENT
Off
P3251-36
When this discrete is grounded by a momentary switch, the
SPI activates.
STANDBY
Off
P3251-14
When this discrete is grounded, the unit will go into standby
mode.
SQUAT
Off
P3251-57
This input determines the on-ground status of the aircraft. It is
active low, and a ground on this input can be configured to
mean On Ground or In Air.
AIR DATA
Off
P3251-58
Switches between two ARINC 429 ADC sources or two EFIS
ADC sources. Source 1 and 2 are set during configuration.
Source 1 is used when the discrete is open and Source 2 is
used when the discrete is grounded.
ALT DATA
All discrete inputs Selects between two pressure altitude sources.
ID SLCT
All discrete inputs
on main board
(P3251)
Selects the system ID and overrides configuration setting.
GTX 1 system ID is selected when this discrete is open. GTX 2
system ID is selected when the discrete is grounded.
GILLHAM
On, Off
Activates all ten Gillham/Gray code inputs. If set to OFF, the
input pins are available for configuration to other discrete input
functions.
TIS-A
All discrete inputs
When this discrete is momentarily grounded, TIS-A will toggle
between operate/standby.
