UT-2501 adopts optoelectronic isolation technology, it fully isolate the electric and ground wire loop circuit between both sides of RS-232 device, protects the communication device from power ground wire loop circuit and surge interference. The built-in instant voltage protector protects CANBUS interface; it adopts advanced TVS (TRANSIENT VOLTAGE SUPPRESSOR) to improve the communication reliability and stability; at the same time, UT-2501 use dual wire balance transmission instead of RS-232 port single side transmission; this greatly enlarge the communication distance. In the field of asynchronous RS-232 point to point in special line, UT-2501 meets the requirement of port protection or distance extension.