1.16E1 fiber optic multiplexer 2.RS232,1 channel service telephone,100M ethernet 3.three years warranty. PDH optical transceiver HS-OPT series PDH optical transceiver ,which is based on super large scale integrated circuit ,a point to point ,link circuit ,loop optical transmission equipment . It can supply 4/8/16/24 interfaces ,one channel 100M ethernet interface ,one channel order wire phone , ...