User's Manual

SYSTEM DESCRIPTION AND INSTALLATION MANUAL
TCAS 3000 Traffic Alert and Collision Avoidance System
34−43−23
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Page 4−20
15 Dec 2005
Table 4−1. TCAS 3000 Computer Unit Loading/Gradient Specifications (cont)
Connector Pin
Designation
Functional Description
LBP−10 +28 V dc Power Input (HI)
This pin along with the TCAS computer unit 28 V dc Power Return line (LBP−3) provide
the +28 V dc power requirements for the TCAS computer unit.
NOTE: This TCAS computer unit operates with either 115 V ac, 400 Hz, or 28 V dc
input power. If +28 V dc is used, the power should be connected through a 10
Amp circuit breaker, and the pins for the 115 V ac input should be left
unconnected.
LBP−11 Chassis Ground
Connect to aircraft frame.
LBP−12 Mutual Suppression Pulse Bus Input
The TCAS computer unit joins the mutual suppression bus daisy chained through TCAS
and other RF transmitting equipment on board the aircraft. TCAS receives suppression
pulses from other LRUs on this bus, which is used to suppress the TCAS receivers during
such transmissions. This prevents the TCAS computer unit from interpreting these
transmissions as valid replies from an intruder aircraft. When not suppressed, the TCAS
computer unit transmits its own suppression pulses on the same bus in order to suppress
the receivers in other L−band systems on the aircraft. This pin is designated as the input.
Pin LBP−13 is directly connected to this pin internally and functions as the output.
L−Band suppression coax must be RG−142, RG400, or equivalent coaxial cable which
meets the operational characteristics required by ARINC 735. LBP−12 and LBP−13 are
connected internally. Connection to only one pin is required.
LBP−13 Mutual Suppression Pulse Bus Output
See LBP−12.
The Interface descriptions that follow are for the 53−pin Data Loader connector J1 mounted on the
front panel of the TCAS computer unit. These descriptions are used to make up the cable that is
used to interface between the TCAS computer unit and an ARINC 615 Portable Data Loader (PDL), a
RS−232 PC Serial Port, a RS−422 Flight Data Recorder, or an ARINC 429 Maintenance Display.
J1−1, 2 ARINC 429 PDL Bus Input: [J1−1 (A), J1−2 (B)]
This differential pair input is a high−speed ARINC 429 bus (100K bits/second nominal)
that is used to input data from the data loader to the TCAS computer unit. The standards
for this interface are defined in ARINC 615 Airborne Computer High Speed Data Loader.
These pins should be connected to pins 1 and 2 of the PDL cable interface.
J1−3,
J1−4
Spare Pins
J1−5 Output Bus Shields
The shields from the output bus (J1−8, 9) should be connected to this pin.
J1−6,
J1−7
ARINC 615 Data Loader Ethernet: [J1−6 TD+,J1−7 TD−]