This radio twilight transmitter is designed to telecontrol various radio switches of the FS20 radio system. It can telecontrol these on two channels based on the intensity of the ambient brightness. The brightness response threshold & the type of switch command execution on the receiver, the switching direction & the filter time to avoid fast switching processes can be programmed separately for each channel. in addition, the timers of the respective FS20 receivers can be programmed from the twilight transmitter.