Discrete Inputs/Outputs - Garmin GTX 32 Installation Manual

Only approved devices may provide altitude to the GTX 32 in accordance with 14 CFR Part 91.217. In
addition, all altitude reporting devices installed in the aircraft must meet certification requirements of
14 CFR Part 91.413. The installer must select an altitude reporting device that is a certified altitude
source for the particular aircraft.
For additional information, refer to GNS 480 (CNX80) Installation Manual 560-0982-01 for the altitude
data reporting configuration.
4.4

Discrete Inputs/Outputs

Table 4-4. Discrete Input/Output Pin Assignments
Pin Name
EXTERNAL IDENT SELECT*
XPDR SYSTEM ID PROGRAM*
AIRBORNE SENSE (SQUAT SWITCH)
EXTERNAL SUPPRESSION (TXP/DME)
INACTIVE: 10 ≤ Vin ≤ 33VDC or Rin ≥100kΩ
*
ACTIVE: Vin ≤ 1.9VDC with ≥ 75 uA sink current, or Rin ≤ 375Ω
Sink current is internally limited to 200 uA max for a grounded input
EXTERNAL IDENT SELECT (remote IDENT) is a momentary input. Refer to Figures C-1, C-2, & C-3
for the remote IDENT switch interconnect.
AIRBORNE SENSE (SQUAT SWITCH) is an ON or OFF input. The squat switch is one of the
Airborne Determination methods available for sensing airborne status. Input for Airborne Determination
allows automatic start and stop of the flight timer and enables automatic STBY mode selection. Refer to
figures C-2 & C-3 for the squat switch interconnect.
XPDR SYSTEM ID PROGRAM* (remote STBY) is an ON or OFF input used typically for dual
transponder installations. When grounded, the GTX 32 is placed in standby.
EXTERNAL SUPPRESSION should be connected if a DME is installed in the aircraft avionics system.
The GTX 32 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 32 mutual suppression output. In this case, leave
the suppression pin open. Refer to figures C1, C-2, & C-3 for the external suppression interconnect.
Page 4-4
Revision F
Connector Pin
P3271
8
P3271
16
P3271
22
P3271
17
GTX 32 Installation Manual
190-00303-60
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