User's Manual

SYSTEM DESCRIPTION AND INSTALLATION MANUAL
TCAS 3000 Traffic Alert and Collision Avoidance System
34−43−23
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Page 4−38
15 Dec 2005
Table 4−6. 55−Pin VSI/TRA Interface Descriptions (cont)
Connector Pin
Designation
Functional Description
J1−20 CHASSIS GROUND INPUT:
Connected to aircraft frame. Also used to connect ARINC cable shields to the chassis.
J1−21 DC GROUND INPUT:
To be connected to aircraft dc Ground.
J1−22 CONFIGURATION STRAP #8 INPUT (NO):
For −84X and −86X units, CS8 is not used and pin J1−22 must remain Open.
For −88X and −89X units, CS8 is paired with CS3 (pin 35) to program the Filter Time
Constant. The following apply: O = Open, G = Ground
CS8 CS3
Pin 22 35 Definition
O O 5.0 Second Delay
O G 6.4 Second Delay
G O 3.2 Second Delay
G G 1.6 Second Delay
J1−23,24 REMOTE LIGHT SENSOR INPUT: (J1−23 HIGH, J1−24 LOW )
This input at pins 23 and 24 provides a means of controlling the VSI/TRA back
lighting via a remote light sensor already present in some aircraft (Douglas and
Boeing). The VSI/TRA has its own built−in sensor and therefore a remote light
sensor need not be used in all installations. Program the VSI/TRA for a remote
light sensor, as described under pin 34 and 35.
J1−25, 44 ARINC 429 TCAS BUS INPUT: [J1−25 (A), J1−44 (B)]
This differential pair input is a high speed ARINC 429 bus (100K bit/second nominal) that
receives Traffic and Resolution Advisory data supplied by the TCAS computer
unit.
J1−26, 45 ARINC 429 VERTICAL SPEED NO. 2 BUS INPUT: [J1−26 (A), J1−45 (B)]
This differential pair input is a low speed bus (12.5K bits/second nominal) that receives
ARINC 429 vertical speed data from the secondary (#2) digital ADC or the #2 PTM.
J1−27, 46 ARINC 429 INERTIAL REFERENCE SYSTEM BUS INPUT: [J1−27 (A), J1−46 (B)]
This differential pair input is a low speed ARINC 429 bus (12.5K bits/second nominal) that
receives vertical speed data from an Inertial Reference System.
J1−28 RA VALID DISCRETE OUTPUT:
This output discrete indicates the ability of the VSI/TRA to perform as a resolution
advisory and/or a traffic advisory display. If the VSI/TRA fails, this discrete presents an
open. Normal operation causes a ground. This discrete is monitored by the TCAS
computer unit.