Digitron 2
I have use Multiplex almost since the beginning, My first set was a Digitron 2 which I bought in 1968.
As you can see it was a single stick transmitter working in the 27 Mhz band. It had 2 channels only for rudder and elevator.
Servo
The receiver was already partly integrated in the signalling processing section. The servos are linear types with also linear potentiometers, slow and noisy. All housings are pure aluminium.
Transmitter
The set is still OK and could be used although it would not be advisable
in an airplane.