User's Manual Part 2

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.
4--71
Table 4--17. Sign Stat us Matrix (SSM) [BCD]
BITS Meaning
30 31
0 0 North/Plus
0 1 No Computed Data
1 0 Functional Test
1 1 Undefined
ARINC 429 inputs are classified as one of the following: high speed (H), low
speed (L) or either (H/L). The A429 receivers are capable of receiving high or
low speed data through APM configuration. The ports are designated H o r L if
they are designated for a function with a known bus speed, otherwise H/L is
assigned (there is no hardware difference between the H, L or H/L ports).
ARINC 429 outputs are also classified as either high speed (H), low speed (L) or
selectable (H/L). A429 outputs designated as H/L speed are capable of
operating in either high or low speed modes, selectable by the APM through the
ASDB database.
(b) Ethernet 10 Base--T Signals
Ethernet 10 Base--T is specified in IEEE Standard 802.3 Ethernet 10 Base--T
provides communication at a data rate of 10 MBPS over two pairs of wires,
where one twisted pair is used to receive data and the other twisted pair is used
to transmit data. Segments of approximately 100 meters in length can be
constructed when twisted pair wire that meets the EIA/TIA Category 3 wire
specifications is used.
(c) RS --422 Signals
The TAWS/RWS card has an RS--422 Input bus which is multiplexed on the
same pins as an ARINC 429 Input bus. The RS--422 Input Bus meets the
electrical requirements in EIA/TIA--422--B.
The RS--422 Input Bus has an input impedance on each pin relative to ground of
≥ 9k Ohms and a differential input impedance between + and -- pins of ≥ 9k
Ohms.
NOTE: This is due to the fact the input is multiplexed with an ARINC 429
Receiver.
The RS--422 Output Bus has an output impedance of 75 ± 5 Ohms distributed
equally between the + and -- outputs.
(d) GPS T ime Mark
The GPS Time Mark Input accepts RS-- 422 GPS Time Mark signals from an
ARINC--743A GPS.