Install Manual
Preliminary
SKY899
Installation Manual
2-27
Rev. A
Power connection:
+28V P8-A
+28V_RET P8-B
SPARE P8-C
2.17 RADIO ALTIMETER (optional)
It is recommended an radio altimeter be connected to the TRC, which will be used in selecting the
appropriate sensitivity level based on your distance above ground. The TRC can accept radio altimeter
input from analog or ARINC-429 source.
NOTE
The radio altimeter must provide full range output between 0 and 2500 feet.
Not all altimeters provide this full range output. The full range output can
sometimes be obtained as a mod to the radio altimeter. Check with the
specific altimeter manufacturer for compatibility and availability of
modification, if necessary.
2.17.1 Analog
This interface allows a DC analog radio altimeter to be used to monitor own aircraft height above ground
and includes input for radio altitude valid signal. Some analog radio altimeters utilize a discrete
valid/invalid signal line to indicate radio altitude validity, while others set the analog data input line to a
high out-of-range value for invalid altitude conditions. If a discrete flag signal is not available leave
RAD_ALT_FLG (P1-14) unconnected and select None in the Service Menu (Rad Alt Flag sub-menu).
Analog radio altitude connections:
RAD_ALT_IN_HI P1-6 (High)
RAD_ALT_IN_LO P1-7 (Low)
RAD_ALT_FLG P1-14 (Valid Flag)
2.17.2 ARINC-429
Radio altimeter ARINC-429 speed must be paired with another input device set to the same speed, either
low (12.5 kHz) or high (100 kHz). Refer to paragraph 2.9 for ARINC-429 receiver channel information.
2.18 SERIAL DATA
The TRC has one RS-232 debug port (J7, terminal device) for service menu access. The TRC has an
auxiliary RS-232 and RS-422 data bus designated for future use (do not connect at this time).
Debug port connection:
DIAG_GND P7-5
DIAG_RX P7-2
DIAG_TX P7-3
CTS P7-7
RTS P7-8
Auxiliary RS-232 connection (future use):
RS232_TX2 P1-86
RS232_RX2 P1-87
RS232_GND2 P1-88
Auxiliary RS-422 connection (future use):
RS422_TXA P1-77
RS422_TXB P1-78
RS422_RXA P1-79
RS422_RXB P1-80