User's Manual

SYSTEM DESCRIPTION AND INSTALLATION MANUAL
TCAS 3000 Traffic Alert and Collision Avoidance System
34−43−23
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Page 4−44
15 Dec 2005
Table 4−8. XS−950 Data Link Transponder Interface Descriptions (cont)
Connector Pin
Designation
Functional Description
P1A−3C,
P1A−3D,
P1A−3E,
P1A−3F
CABLE DELAY PROGRAM INPUTS:
The Cable Delay Program Inputs are used to compensate for the difference in
propagation delays in the transponder due to antenna transmission line length differences
between the top and bottom antennas. The inputs use ground/open logic levels. The
Cable Delay Program Common (pin P1A−3F) can be used to supply a ground.
Program Pin Differential Transponder
P1A−3C P1A−3D P1A−3E Delay Adjustment
Open Open Open 0−50 nsec No Change
Open Open Ground 51−150 nsec Add Delay to Top Channel
Open Ground Open 151−250 nsec Add Delay to Top Channel
Open Ground Ground 251−350 nsec Add Delay to Top Channel
Ground Open Open 0−50 nsec No Change
Ground Open Ground 51−150 nsec Add Delay to Bottom Channel
Ground Ground Open 151−250 nsec Add Delay to Bottom Channel
Ground Ground Ground 251−350 nsec Add Delay to Bottom Channel
The differential delay column is the difference in the round trip cable delay between the
top and bottom antenna cables. The differential delay can be calculated as follows:
[Top length in feet − Bottom length in feet] X [Characteristic Delay (nsec/foot)] X 2.
P1A−3G,
P1A−3H,
P1A−3J
SDI PROGRAM INPUTS:
The SDI program inputs are used to identify the system number in the installation. The
inputs use ground/open logic levels. The SDI Common (pin P1A−3J) can be used to
supply a ground.
Program Pin
P1A−3G P1A−3H Definition
Open Open Not Applicable (SDI = 00)
Open Ground LRU System #1 (SDI = 01)
Ground Open LRU System #2 (SDI = 10)
Ground Ground LRU System #3 (SDI = 11)
P1A−4A
THRU
P1A−4J
ARINC 565 ANALOG AIR DATA COMPUTER #1 INPUTS:
These input pins allow for altitude information from an Analog Synchro Altitude Interface
to be connected to the transponder. The standards for this interface are defined in
ARINC 565, “Subsonic Air Data System”.