User's Manual
SYSTEM DESCRIPTION AND INSTALLATION MANUAL
TCAS 3000 Traffic Alert and Collision Avoidance System
34−43−23
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Page 4−43
15 Dec 2005
Table 4−8. XS−950 Data Link Transponder Interface Descriptions
Connector Pin
Designation
Functional Description
P1A−1A THRU
P1A−1K, AND
P1A−2K
ENCODING ALTIMETER #2 INPUTS:
These Mode C pulse discrete inputs allow for altitude inputs from an encoding altimeter
that contains a discrete 11 wire interface. The standards for this interface are defined in
ARINC Characteristic 572, “Air Traffic Control Transponder”. The inputs use ground/open
logic levels.
NOTE: Two encoding altimeters are required if the transponder is used with TCAS.
P1A−2A, 2B ARINC 429 ADLP TO COMM A/B BUS INPUT: [P1A−2A (A), P1A−2B (B)]
or
ARINC 429 FMC/GNSS Input
Four ARINC 429 busses are provided for interfacing to a Mode S Airborne Data Link
Processor (ADLP). The COMM A/B input and output busses are used for the transfer of
standard length messages to and from the ADLP. The COMM C/D input and output
busses are used for the transfer of extended length messages (ELM) to and from the
ADLP. P1A−2A and 2B can also be configured to a FMC/GNSS input. The standard for
this interface is defined on ARINC 718−A. For additional information on the FMC/GNSS
input, refer to ARINC 743A. This input is configured by grounding or oponing P1B−5H.
P1A−2C, 2D ARINC 429 ADLP TO COMM C/D BUS INPUT: [P1A−2C (A), P1A−2D (B)]
or
ARINC 429 IRS/RMS/Data Concentrator
See pins P1A−2A, −2B
P1A−2E, 2F ARINC 429 COMM C/D TO ADLP BUS OUTPUT: [P1A−2E (A), P1A−2F (B)]
or
ARINC 429 General Output Bus
See pins P1A−2A, −2B
P1A−3B XPDR FAIL DISCRETE OUTPUT #2:
This discrete output is set to annunciate an internal transponder failure or the Mode S
address is illegal (All 0’s or 1’s). A ground logic threshold (<3.0 V dc) is output when the
transponder is operating normally, and an open logic threshold (resistance >100K ohms to
unit ground) when a failure has occurred. The output is capable of sinking 200 mA of
current. Connect this pin to the Control Panel XPDR FAIL #2 input.