Why does the easyFly3 USB interface cable (stick version) cannot recognize my transmitter?

Some transmitters need to use the interface adapter (oder no. #3024040).

Otherwise the interface adapter will not work. The easyFly3 USB stick is equipped with an opto coupler at the input side.

This can have as a consequence, that a too weak signal is available for the further evaluation. The optional available adapter (order no. #3024040) provides for a sufficient large signal.