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