User's Manual
SYSTEM DESCRIPTION AND INSTALLATION MANUAL
TCAS 3000 Traffic Alert and Collision Avoidance System
34−43−23
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Page 4−14
15 Dec 2005
Table 4−1. TCAS 3000 Computer Unit Loading/Gradient Specifications (cont)
Connector Pin
Designation
Functional Description
RBP−5A Advisory Inhibit Discrete Input No. 1 (NO)
Four discrete inputs at RBP−5A, −5B, −5C, and −5D provide the capability for the TCAS
computer unit to defer all advisory (TA), aural alert and visual alert outputs until another,
higher priority announcement or alert is completed. An open at all four of these discrete
inputs indicates normal advisory/alert operation. These discrete inputs become active by
connection to program common (ground) at RBP−7K. No new TA information can be
placed on the RA or RA/TA busses during a period of Advisory Inhibit. If an advisory
condition, which occurred during a period of Advisory Inhibit, remains when the TCAS
computer unit returns to normal operation, it is annunciated. The Advisory Inhibit inputs
and their effect on the advisory/alert priority system are as follows:
Discrete No. Pin No. Mode Priority
1 RBP−5A Forced Standby 1
2 RBP−5B Force TA Only (no voice/tone) 2
3 RBP−5C Force TA Only (no voice/tone) 2
4 RBP−5D Force TA Only (no voice/tone) 2
Discrete No. 1 (RBP−5A) has priority over No. 2 (RBP−5B), No. 3 (RBP−5C) and No. 4
(RBP−5D). Discrete No. 1 forces TCAS into STANDBY mode. Discretes No. 2, No. 3,
and No. 4 force TCAS into TA mode with no voice or tone annunciations.
RBP−5B Advisory Inhibit Discrete Input No. 2 (NO)
See RBP−5A.
RBP−5C Advisory Inhibit Discrete Input No. 3 (NO)
See RBP−5A.
RBP−5D Advisory Inhibit Discrete Input No. 4 (NO)
See RBP−5A.
RBP−5E Increase Climb Inhibit Discrete Input No. 1 (NO)
This input is a ground/open type discrete used to provide information to the TCAS CU
whether to assume that the aircraft cannot achieve a climb rate of 2500 feet per minute
(FPM). The climb inhibit discrete inputs are designed in pairs (No. 1 and No. 2 at
RBP−5F, or No. 3 at RBP−5G and No. 4 at RBP−5H) but can be wired as a single input
or in conjunction with other aircraft operations to achieve airframe customization of the
climb inhibit feature. The 2500 FPM climb inhibit function is assumed whenever No. 1
and No. 2 are ground or No. 3 and No. 4 are ground.
RBP−5F Increase Climb Inhibit Discrete Input No. 2 (NO)
See RBP−5E.
RBP−5G Increase Climb Inhibit Discrete Input No. 3 (NO)
See RBP−5E.
RBP−5H Increase Climb Inhibit Discrete Input No. 4 (NO)
See RBP−5E.
RBP−5J Climb Inhibit Discrete Input No. 3 (NO)
See RMP−1J.