Outline: A light four electricity 10/100M auto-adapted fast ethernet optical fiber transceiver (also said that electro-optical medium switch), built-in four 10M/100M the bps auto-adapted switchboard, may carries on four independent 10Base-T and the 100Base-TX twisted pair line electrical signal with the 100Base-FX light signal the interconversion. It expands the network transmitting range from the copper wire 100m limit to 120Km (single model full-duplex way). Supports two kind of different network connections media type: 10/100Base-TX and 100Base-FX, realize between two kind of network connections media data transmission through the use exchange technology and the memory repeater technology. Supports the double filament multi-molds, the double filament single model and the single filament single model many kinds of fiber optic transmissions. characteristic: adapts 10Mbps and the 100Mbps environment automatically, is advantageous for the network promotion the built-in highly effective exchange core, realizes the flow control, reduces the broadcast to wrap to provide four independent 10M/100Mbps auto-adapted exchange type twisted pair line mouth, realizes the electricity mouth backup and multiuser turns on to support the full-duplex and the half-duplex mode of transmission, can consult automatically automatically the support twisted pair line mouth overlapping, the convenient system deb ing installs the support longest 1552byte ultra long data packet to transmit to support QoS, guaranteed that the VOIP data packet transmits to support the STP spanning tree, constitution redundant network the low power loss, gives off heat lowly, can the long time steady work; supports the double filament multi-molds, the double filament single model and the single filament single model many kinds of optical fiber mouth choice, expanded user's demand.