Go to futaba website and look up the 7c manual. I just bought this radio and the instructions say that you can set all 7 channels to a N, F, or - setting. the N means normal and this means that the set channel can be controlled by the student box using any programing on the student box. the F is for function. this means that the student box can control this channel using the programed mixes set at the master radio. for example the student box would operate dual aileron servos on seperate channels with flaperon just by moving the aileron stick. the - setting means the student box cannot use this channel even with the trainer switch ativated.