You need to turn off the power button on your transmitter for the interface to work correct. Whan you plug in the interface cable into the transmitter, you will notice that it turns on automatically. In this mode, only the coder part of the transmitter is turned on, and it is not actually transmitting a signal.

Secondly, you must leave the Trainer switch in it's normal position.

Thirdly, what interface do you have. If it is a FMS interface, it will not work with Aerofly.