User's Manual

TT21/TT22 Transponder Installation Manual 13 July 2009
00560-00 Issue AF
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Trig Avionics Limited Page 3
Front Panel
Datalink
A two wire data link is used to connect the TT21/TT22
and the controller.
Front Panel
Power
The controller is powered from the transponder.
Remote On/Off
The on-off switching is on the controller, and switches this
input.
Ident input
External IDENT switch input.
Standby input
External standby input for dual transponder installations.
“On ground”
input
Allows automatic flight/ground mode switching for
aircraft with a squat switch.
Suppression bus
I/O
ARINC compatible suppression bus signal used in aircraft
with other pulse equipment, such as DME. This pin is
both an input to and output from the transponder.
GPS Input
Connection to a GPS supplying position input for ADS-B
position reporting.
RS232 Output
Secondary RS232 interface provided for future upgrade.
2.2.2 TC20 Controller Unit
The TC20 controller has a single 9 way D-type connector. It provides the
following services:
Power Input
The controller receives power from the transponder.
Front Panel Datalink
A two wire data link is used to connect the
TT21/TT22 and the controller.
Remote On/Off
The on-off switching is on the controller, and controls
this output.
Altitude Output
An additional serial output on the TC20 provides
pressure altitude information that can be used for baro-
aiding by certain GPS receivers.