... PDH fiber optical multiplexer ,8E1 2.rs232,service telephone 3.reasonable price,swift delivery PDH fiber optical multiplexer HS-OPT series PDH optical ... data terminal equipment )2.supply order E1 opposite terminal loop back function ,optical home terminal self-loop ... impedance75Ωunbalance/ 120Ωbalanceinterface typeBNC Ethernet interface interface rate100M auto-adaptinterface protocolIEEE802 ...