User's Manual Part 1

T
2
CAS / Part No. 9000000
SYSTEM DESCRIPTION AND INSTALLATION MANUAL
34-43-20
15 Feb 2003
Use or disclosure of information on this page is subject to the restrictions in the proprietary notice of this document.
1--27
(b) TCAS System Interfaces
1
Mode S Transponder Interface
The T
2
CAS computer contains two sets of ARINC 429 high speed buses for
communication with two Mode S transponders. It uses ARINC 718A/735A
communication protocol (2 inputs, 2 outputs).
2
Onboard Maintenance System Interface
The TCAS function contains a set of ARINC 429 low speed buses for
communication with an onboard maintenance system (1 input, 1 output).
The unit interfaces with all major airframe manufacturers maintenance
computer systems. Since the maintenance computer protocol for each
airframe manufacturer is different, the TCAS function automatically detects
the type of airframe from the data received from the maintenance computer
and sets its protocol accordingly.
3
Data Loader Interface
The TCAS function contains a set of ARINC 429 buses and discrete inputs
that interface to either an airborne data loader (ADL ) through pins on the
rear connector, or a portable data loader (PDL) through the 53--pin circular
connector on the front panel of the unit. The computer works with ARINC
603 data loader protocol (low speed bus) or ARINC 615 data loader protocol
(high speed bus). The ADL and PDL ARINC 429 inputs have separate data
loader buses to allow for connection of both types of data loaders. It also
has separate data loader enable discrete inputs. The type of data loader
protocol (603 or 615) is selected by a discrete input. The unit software part
number can be output on the data loader port by grounding a discrete input.
The aural voice commands are contained in Flash Erasable Programmable
Read-- Only Memory (EPROM) on the TCAS. Each software load contains in
addition to program code, voice command data. Changes to voice
commands can be made through a software load instead of removal of the
LRU from the aircraft for hardware modification.
4
TCAS Display Bus Interface
The TCAS function has four sets of ARINC output buses for display of traffic
and resolution advisories.
The TA/RA Display No. 1 and No. 2 buses are high speed ARINC 429 buses
that contain both traffic information and resolution advisory information. The
buses function according to either the ARINC 735A characteristics, or can
optionally be set for the Honeywell EFIS characteristics through a program
input pin (RMP -- 12C). For each bus, a valid discrete input is provided that
indicates whether the display is functional.
The RA Display No. 1 and No. 2 buses are low speed ARINC 429 buses that
contain only resolution advisory information. The buses function according
to the ARINC 735A characteristics. For each bus, a valid discrete is
provided that indicates whether the display is functional.