User's Manual

SYSTEM DESCRIPTION AND INSTALLATION MANUAL
T
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CAS/Part No.9005000
Table 4-1: T
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CAS Computer Unit Interface Description (cont)
(Applicable to Part No. 9005000-10000, -10101, -10202, -10204, and -11203)
Connector
Pin
Designation
Functional Description
RMP-2A
Traffic Aural Advisory Discrete Output (NO)
Same as RMP-1F, except this discrete is active during a traffic advisory when
information is being given to the flight crew regarding other aircraft in the
immediate vicinity. No suggested maneuver is issued. This output is inhibited if
either the corrective or preventative output is active.
RMP-2B, 2C
GPS Time Mark #1 Input : [RMP-2B (A), RMP-2C (B)]
These RS-422 differential pair inputs are provided to receive the Time Mark signal
from an external GPS receiver in order to provide synchronization with other
aircraft systems. This signal is also used to remove the latency error from GPS
when available.
RMP-2D
Advisory/Announce Common
This is the return line for the aural and visual advisory discrete outputs.
RMP-2E
Reserved Discrete Output (Lamp Driver)
RMP-2F,2G
8-Ohm Audio Output: (RMP-2F [HI], RMP-2G [LO])
This is a synthesized voice output supplied by the TCAS computer unit. Its level is
programmable up to 8 W into an 8-ohm speaker. All aural traffic and resolution
advisories are announced over this output. See RBP-7A for audio level
programming.
RMP-2H, 2J
Radio Altimeter No.1 ARINC 552/Analog Input: (RMP-2H [HI], RMP-2J [LO])
Normal aircraft configurations include either two digital or two analog radio
altimeter sources. The T
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CAS computer unit attempts to establish which type is
present in order to obtain data from one of the two available sources. TCAS first
checks the radio altimeter No.1 valid flag at RMP-2K. If No.1 is not valid then No.2
valid is checked at RBP-3C. If neither are valid then TCAS checks digital source
No.1 for valid data on the ARINC 429 bus at RMP-13H and RMP-13J. If none of
the above are valid then the TCAS checks the digital source No.2 for valid data on
the ARINC 429 bus at RBP-3D and RBP-3E. This process is repeated until a valid
flag or data is detected.
Until a valid source is found, the TCAS function inhibits all surveillance, CAS, and
TA/RA display functions, records failures in maintenance memory, and sets the
TCAS system status discrete output at RMP-13K to invalid. The TCAS function
uses radio altitude to inhibit advisories and aural annunciation when in close
proximity to the ground. This analog input No.1, as well as analog input No.2, can
accept data as a dc voltage from several types of radio altimeters. The type of
radio altimeter is selected using the program pins RMP-12B and RMP-12D thru
RMP-12F.
RMP-2K
Radio Altimeter No.1 Valid Input (PO)
See RMP-2H. A valid condition is greater than +18.5 V dc. An invalid is open
circuit.
4-12
04 Nov 2014
34-45-29
Pub. No. 8600200-001, Revision 004
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