Address check system

Claim 1

An address check system for a transmission system having means for transmitting control and address information to at least one receiver, said address information being representable as a binary address-defining number, address entering and storing means associated with said receiver for storingly entering a local address as a binary electrical representation thereof in the form of local address-setting bits, address comparison means associated with said receiver for comparing said transmitted address-defining number with said local address, and control means associated with said receiver for blocking the passage of said control information responsively to detecting a mismatching condition by said address matching means, the improvement comprising: said means for entering and storing said local address including means for entering said local address in a parallel line representation, said representation including said address-setting bits representing a binary number and further including one or more protocol-setting bits placed on a chosen one or more of said parallel lines; protocol comparison means for selectively testing at least one of said local address-setting bits and at least one of said protocol-establishing bits to detect a protocol-matching condition therebetween according to a given protocol defined solely by said protocol comparison means and bearing no specific relationship to transmitted signals; and means for actuating said control means to block said passage of said control information when a mismatch condition is detected by said protocol comparison means.