This solution provides a simple to use interface for a Trig Avionics TT21 or TT22 transponder.

This interface simply plugs into the rear of the transponder and typically only 4 wires have to be connected:

2 x CAN bus wires, power and ground. An optional suppression line is also provided should that be needed.

Please note that this interface does not work with the similar looking Dynon transponder. It is designed to be operated with the Trig transponder.