The SFP 1.25Gb/s transceiver modules are hot-pluggable I/O devices that plug into module sockets. The transceiver connects the electrical circuitry of the module with the optical or copper network. GBIC transceiver, short name for the Gigabit Interface Converter, is a media conversion device between Gigabit Ethernet and fiber optic networks. Via the GBIC transceiver, Gigabit network equipment can directly connect to copper wires, single mode fiber ports or multimode fiber ports. SFP 1.25Gb/s can be regarded as the upgrade version GBIC. Unlike GBIC with SC fiber optic interfaces, cisco SFP is with LC interface. Moreover, its main body size of SFP is only about half of GBIC, which makes SFP space saving Copper transceiver is high performance, cost effective module compliant with the Gigabit Ethernet and 1000BASE-T standards as specified in IEEE 82. 3-22 and IEEE 82.3ab, which supporting 1Mbps data- rate up to 1 meters reach over unshielded twisted-pair CAT 5 cable. Copper SFPs enable system manufacturers to populate SFP ports with either copper or optical transceivers. 1000Base-T copper SFP is used for copper networks, which refers to GbE over copper, primarily Category 5, 5E, and, increasingly, Category 6 twisted-pair cable. Typical 1000Base T SFP includes Cisco GLC T and SFP 1.25Gb/s,these SFP modules are used in Gigabit networks and they are fully compatible with 1000Base-T. SFP GE T is the copper SFP that are with extended working temperature and DOM support.