User's Manual

SYSTEM DESCRIPTION AND INSTALLATION MANUAL
TCAS 3000 Traffic Alert and Collision Avoidance System
34−43−23
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Page 4−47
15 Dec 2005
Table 4−8. XS−950 Data Link Transponder Interface Descriptions (cont)
Connector Pin
Designation
Functional Description
P1A−7H, 7J ARINC 429 ADC #1 BUS INPUT: (P1A−7H [A], P1A−7J [B])
The altitude information for the transponder can be obtained from an ARINC 706 Air Data
System through two low speed ARINC 429 data busses. The standards for this interface
are defined in ARINC Characteristic 706, “Mark 5 Subsonic Air Data System”.
This differential pair input is a low speed ARINC 429 bus that inputs uncorrected pressure
altitude (ARINC label 203) from an altitude source. Also see pins P1B−5A, 5B.
P1A−71 TOP ANTENNA RF INPUT:
RF input from top antenna.
P1B−1A
THRU
P1B−3E
MODE S ADDRESS INPUTS:
The Mode S Address is a unique 24−bit code assigned to each aircraft. Pins P1B−1A
thru P1B−3E are used to program this 24−bit binary number. The inputs must be set
according to this binary number representation. Each binary 1 represents a Grounded pin
and each binary 0 represents an Open pin. Pin P1B−1A represents the most significant
bit (MSB) of the binary number and pin P1B−3D represents the least significant bit (LSB)
of the binary number.
NOTE: An address of all 0’s or all 1’s is an illegal address, and can cause the aircraft to
be invisible to TCAS II equipped aircraft in flight. Never use an illegal address
for an installed system.
P1B−3H FUNCTIONAL TEST DISCRETE INPUT:
This discrete input is used to put the transponder in a functional test mode. The
functional test that is performed by the transponder is equivalent to a test that is initiated
from the control panel. The input uses ground/open logic as follows:
Ground = Initiate Functional Test
Open = Normal Operation
P1B−3J ALTITUDE COMPARISON FAIL DISCRETE OUTPUT:
This discrete output annunciates a comparison failure in the altitude data for the
transponder if Gillham altitude data is selected. The output annunciates a failure if the
two altitude sources are not within 500 feet.
The output drives a ground logic threshold (voltage of less than 3.0 V dc) when the
altitude is valid, and an open logic threshold (resistance is greater than 100K ohms to unit
ground) when a failure has occurred. The output is capable of sinking 200 mA of current.
P1B−3K XPDR FAIL DISCRETE OUTPUT #1:
This discrete output is set to annunciate an internal transponder failure or that the Mode S
address is illegal (All 0’s or 1’s). The output will source a voltage of greater than 5.0 V dc
at 100 mA of current when a failure has occurred, and an open circuit (resistance of
greater than 100k ohms to unit ground) when the transponder is operating normally. The
output contains diode isolation. Connect this pin to the Control Panel XPDR FAIL #1
input.
P1B−4A THRU
P1B−4K, AND
P1B−5K
ENCODING ALTIMETER #1 INPUTS:
First of two Encoding Altimeter interfaces. See pins P1A−1A thru 4K and P1A−2K.