Abstract: A remote control system for controlling the operation of electrical apparatus, comprising a receiver provided in use at said apparatus and a transmitter having a casing and adapted for use as an add-on module in conjunction with a telephone capable of dialling based on DTMF (Dual-Tone-Multi-Frequency). The transmitter comprises an input device for receiving a DTMF dialling signal from said telephone, and a transmitter circuit housed in the casing for subsequently processing the signal and then transmitting it as a remote control signal for receipt by the receiver. The receiver comprises a receiver circuit for receiving the remote control signal transmitted by the transmitter, and a control circuit for subsequently processing the control signal and then controlling the operation of said apparatus according to the control signal.

Abstract: A remote control system for controlling the operation of electrical apparatus, comprising a receiver provided in use at said apparatus and a transmitter having a casing and adapted for use as an add-on module in conjunction with a telephone capable of dialling based on DTMF (Dual-Tone-Multi-Frequency). The transmitter comprises an input device for receiving a DTMF dialling signal from said telephone, and a transmitter circuit housed in the casing for subsequently processing the signal and then transmitting it as a remote control signal for receipt by the receiver. The receiver comprises a receiver circuit for receiving the remote control signal transmitted by the transmitter, and a control circuit for subsequently processing the control signal and then controlling the operation of said apparatus according to the control signal.

Abstract: Ultrasonic transmitting and receiving apparatus comprises a transmitter operable in response to a program to emit an ultrasonic signal and a receiver preprogrammed with a plurality of functions actuable in response to a said ultrasonic signal from the transmitter. The transmitter may comprise a PC 10 with a loudspeaker 18 and the receiver may comprise a stuffed toy 12 housing a microphone 14 and a microprocessor decoder and controller 16. Decoded signals may actuable motion, visual and audio functions of the toy.