iX12 Manual

Channel: Must correspond to the channel selected in the AS3X application in
the FM Channel Assignment screen
Switch: Selects the switch on the transmitter that is used to select the flight
modes in the AS3X system. AS3X and Flight Mode share a switch
assignment. Assigning a switch in the AS3X menu will set the Flight
Mode switch assignment. Conversely, assigning a switch in the Flight
Mode menu will set the switch assignment in the AS3X menu.
Relative (REL) must be selected in the AS3X application gain screen to allow
adjustable gain from the transmitter.