Abstract: 6. A communication security system including a transmitting system having a lurality of sources of carrier frequencies, a source of prescheduled noise, a suppressed carrier modulator and transmitter responsive to said carrier frequencies and to said prescheduled noise for transmitting only the resultant sidebands, and means for connecting said respective carrier sources to said modulator in accordance with a schedule to be communicated, and a receiving system having a synchronized source of identical prescheduled noise, a receiver multiplier responsive to said sidebands and said prescheduled noise to restore said carrier frequencies, and a plurality of filters each corresponding to one carrier frequency, whereby the outputs of said filters reproduce at said receiving system the schedule communicated from said transmitting system.

Abstract: 1. A security remote control system comprising a pair of carrier generato means for balance modulating both the carriers from said generators by a single source of noise at a first station and means for transmitting only the side bands, a receiver at a second station for said side bands, means for combining the side bands of said pair of carriers to provide a beat frequency signal corresponding to the frequency difference of said pair of carriers, narrow band filter means to isolate said signal, and means responsive to said signal for controlling an operation at said second station.