... optical multiplexer HS-OPT series PDH optical multiplexer ,which is based on super large scale integrated circuit ,a point to point ,link circuit ,loop optical transmission ... E1 opposite terminal loop back function ,optical home terminal self-loop function3.supply one ... ,-48VDC,+24VDC8.transmission distance : 2~120Km9.networking management function of SNMPTechnical parameters Optical fiber interface ...