User's Manual

SYSTEM DESCRIPTION AND INSTALLATION MANUAL
TCAS 3000 Traffic Alert and Collision Avoidance System
344323
Use or disclosure of information on this page is subject to the restrictions in the proprietary notice of this document.
Page 445
15 Dec 2005
Table 48. XS950 Data Link Transponder Interface Descriptions (cont)
Connector Pin
Designation
Functional Description
P1A5A,
P1A5B,
P1A5C,
P1A5D
MAXIMUM TRUE AIRSPEED PROGRAM INPUTS:
The Maximum True Airspeed inputs are used for strapping the maximum cruise airspeed
capability of the aircraft. The inputs use ground/open logic levels. The Max True
Airspeed Common (pin P1A5D) can be used to supply a ground.
Program Pin
P1A5A P1A5B P1A5C Definition
Open Open Open No Maximum Airspeed Available
Ground Open Open Maximum Airspeed 75 Knots
Open Ground Open Maximum Airspeed >75 and 150 Knots
Ground Ground Open Maximum Airspeed >150 and 300 Knots
Open Open Ground Maximum Airspeed >300 and 600 Knots
Ground Open Ground Maximum Airspeed >600 and 1200 Knots
Open Ground Ground Maximum Airspeed >1200 Knots
Ground Ground Ground Not Assigned
P1A5E, 5F ARINC 429 TX COORDINATION BUS INPUT: (P1A5E [A], P1A5F [B])
Two high speed ARINC 429 busses (100K bits/second nominal) are provided to interface
between the transponder and a TCAS computer unit. The standards for this interface are
defined in ARINC Characteristic 735, “Traffic Alert and Collision Avoidance System”.
P1A5G, 5H ARINC 429 XT COORDINATION BUS OUTPUT: (P1A5G [A], P1A5H [B])
See pins P1A5E, 5F.
P1A5J AIR / GROUND #2 DISCRETE INPUT:
This pin and AIR / GROUND #1 Discrete Input (pin P1A5K) provide a method for the
transponder to automatically determine the Air/Ground status of the aircraft. The status is
used in replies to Mode S interrogations and to inhibit replies to certain types of
interrogations. Both inputs use ground/open logic, where a Ground specifies an “On the
Ground” condition and an Open specifies an “In the Air” condition.
When this pin is connected to the Air/Ground Relay (Squat Switch), the transponder will
not reply to ATCRBS, ATCRBS/Mode S All Call, or Mode S All Call when the input is set
for “On the Ground”. This input should be connected to the Air/Ground Relay for normal
operation.
P1A5K AIR / GROUND #1 DISCRETE INPUT:
See pin P1A5J.
When this pin is connected to the Air/Ground Relay (Squat Switch), the transponder
replies to all types of interrogations irregardless of the state of the input. This input allows
the transponder to reply during a ramp test.
P1A6A, 6B FMC #1/Gineral In #2
This differential pair input supports common existing FMC configurations where flight ID is
available on the FMC General Purpose output bus but the other Enhanced data is only
available on a display bus.