A digital start-stop multiplexing system including a sender which sequentially scans a plurality of monitoring points and generates a train of digital pulses coded to represent information provided at the monitoring points for transmission over a transmission line to a receiver which is responsive to...http://www.google.co.uk/patents/US3938144?utm_source=gb-gplus-sharePatent US3938144 - Digital multiplexing system remote scanning of a plurality of monitoring points
