Remote-control security system and method of operating the same

Abstract

A security system has a remote-control unit, a receiving unit and an operating unit connected to the receiving unit and designed to perform a security function. The remote-control unit comprises a keyboard, an encoder and a transmitter. The encoder is programmed with an algorithm and a base code and, in response to consecutive actuations of the keyboard, operates consecutively with the algorithm, beginning from the base code, to generate a series of modified codes. The encoder also produces a corresponding series of encoded signals containing the base code and a respective modified code. The encoded signals are sent to the receiving unit by the transmitter. The receiving unit includes a receiver for the signals and a decoder which is activated in response to an incoming signal. The decoder is programmed with the same algorithm and base code as the encoder and, similarly to the encoder, generates a series of modified codes in response to consecutive incoming signals. After the decoder generates a modified code upon being activated by an incoming signal, the decoder compares its base code and modified code, respectively, with the base code and modified code of the signal. The decoder sends a control signal to the operating unit if and only if the two base codes are identical and the two modified codes are identical.