The TT21 system is the smallest, lightest, Mode S general aviation transponder. This two part system, which includes an integrated altitude encoder, can fit into the smallest of aircraft – and yet it is fully certified and compliant with all the transponder requirements.
The TT31 is a power efficient, inexpensive, Mode S general aviation transponder. The TT31 meets the European elementary surveillance requirements, and fits the same mounting tray as the popular KT76A transponder, making it ideal for both new and retrofit installations.