SKY899
Installation Manual
Page 2-30 - Installation
009-11900-001
July 18, 2013
Revision F
When using an alternate display device reference Figure 2-4 as well as manufacturer instructions
concerning these connections. Required soft-key connections will depend upon the alternate display
capabilities (e.g., some displays control operation mode internally and ranges externally, while others
handle ranges internally and operation modes externally).
When installing multiple alternate displays, soft-keys inputs may require several displays being connected
to the same input (e.g., WX-1000/SKY497 connected to all soft-key inputs; RGC250/350 to soft-keys 2,
3, & 4; GNS430 to soft-keys 2 & 4 and Collins EFIS to soft-keys 2, 3, & 4). Refer to Table 2-1 for soft-
key connections.
NOTE
Pilot must be able to perform the functions listed in Table 2-1, with
either the display switches or external momentary switches. Check with
display manufacturer for display's capabilities, before wiring soft-key
inputs.
Table 2-1: Soft-Key Connection Options
SIGNAL NAME
FUNCTION
WX-1000/SKY497
DISPLAY
ALTERNATE DISPLAY(S)
SFTKEY1_IN (P1-18)
MSG
Connect
Do not Connect
SFTKEY2_IN (P1-19)
TEST/ALT
(NRM/ABV/BLW/
UNR)
Connect
Connect (Momentary Switch - external switch or alternate
display open-collector output). Label external switch TEST/ALT,
TEST or ALT depending on alternate display capabilities.
SFTKEY3_IN (P1-20)
RANGE
Connect
Optional - Display specific. Label external switch RANGE.
SFTKEY4_IN (P1-21)
OPR/STB
Connect
Connect (Momentary Switch - external switch or alternate
display open-collector output). Label external switch OPR/STB.
2.21 SUPPRESSION BUS I/O
The TRC outputs a 100 µs (± 5 µs) suppression pulse on the aircraft suppression bus. In addition, the
TRC899 receives suppression signals from all other devices on the suppression bus (e.g., transponder,
DME). (Reference ARINC 735-2 and DO-197.)
CAUTION
The aircraft transponder must have suppression circuitry to ensure that
SKY899
does not paint itself as a target (e.g., TA).
Suppression Bus connection:
SUPBUS
P1-93
The document reference is online, please check the correspondence between the online documentation and the printed version.