Circuitry for the validation of repetitive signals including input/output circuitry providing information regarding signals received that is connected to a progammable microprocessor, a read only memory and random access memory. The microprocessor is programmed so the circuitry determines the receipt...http://www.google.ca/patents/US4734881?utm_source=gb-gplus-sharePatent US4734881 - Microprocessor controlled signal discrimination circuitry
