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The Trig TT21 is a two part transponder system, which includes an integrated altitude encoder. In design and technology the TT21 is identical to the Trig TT22; the only difference is that the transmitted output power of the TT21 is lower, qualifying the unit as Class 2 transponder. Class 2 transponders may be used on aircraft cruising slower than 175 knots, and operating below 15,000 feet IFR or VFR.
The front panel controller is smaller than a standard instrument, and the remote transponder is not much bigger than a pack of cards. The TT21 can fit into the smallest of aircraft - and yet it is fully certified and compliant with all the transponder requirements. The TT21 can be mounted in a standard 57mm (2 1/4 inch) instrument hole, or wher space is really tight, in a compact mounting just 42 mm high.
Low Weight - less than 500 grams
Minimal Panel Space
Low Power consumption
130 Watts Nomnal Output
Integrated Altitude Encoder
Support for 1090ES/ADS-B Out
European ETSO and FAA TSO approved