Caledonian Airborne Systems have designed and manufactured this system and have customised it to each application. Applications have included the switching on of ground equipment from the air at remote unmanned air strips from aircraft or helicopters without the need to modify the aircraft.
The system comprises of a hand held controller situated in the aircraft, and a ground based radio receiver and decoder with built in relays. The ground station has a small speaker built in to monitor voice or code received, and LED indication of squelch, valid tones and relay status.
To test the system the hand controller is placed over a microphone on the station and a test button is pressed. The radio is bypassed and audio is injected into the decoder which will respond to the controller inputs.