The RU-SC2 is the ideal choice in installations when two RS-232 devices requiring full-duplex communication are to be connected at a long distance. Connection to the RS-232 device is made on the front panel. The RS-422 input and output connections and power connections are made on the rear panel through full-size, clearly identified, barrier block terminals. Two RU-SC2s may be connected (using the RS-422 connections) at each end of 2-pair of long, balanced, twisted-pair line to permit feeding data between two RS-232 ports, thereby permitting serial communications over much greater distances than with conventional serial cables.