Communication system comprising a remotely activated switch

Claim 1

A communication system, comprising: means for producing digital signals; means for receiving digital signals; a communication medium for conveying signals from the producing to the receiving means; activating means capable of opening or closing an external circuit when said activating means are energized; control means adapted to receive signals from the communication medium, the control means being further adapted to energize the activating means in response to signals received from said communication medium, such that when the control means receive a sequence of digital bits having predetermined properties, the activating means are energized; and means for electrically powering the control means such that the activating means can be energized independently of whether the receiving means are powered ON or OFF, Characterized in that the control means comprise: (a) means for receiving, from the producing means via the communication medium, signals representing alphanumeric characters; (b) a converter for converting received signals to parallel binary representations of alphanumeric characters, whereby characters encoded in the received signals may be converted, the converter having output terminals; (c) a first decoder for producing an output pulse in response to the appearance, at the output terminals of the converter, of a converted activating character; (d) a counter for producing an output pulse after a designated number of output pulses from the first decoder; (e) a second decoder for resetting the counter whenever a converted resetting character appears at the output terminals of the converter; and (f) means for energizing the activating means whenever an output pulse is produced by the counter.