ConnectGears GC-G21SC is a 1000Mbps Gigabit Ethernet Media Converter offering a simple and cost-effective method to convert between 1000BaseT UTP Cat. 5/5e cables and 1000BaseSX multimode 50/125, or 62.5/125um (805nm wave length) fiber cables.As defined in IEEE 802.3ab Gigabit Ethernet standards, 1000BaseT specifies the transmission over UTP cable can transmit signals up to 100 meters. 1000BaseSX specifies the transmission in fiber media can transmit signals up to 550 meters using multimode fiber cables.. The GC-G21SC comes with one MDI/MDIX auto-crossover support RJ45 connector that allows connection to a 1000BaseT device such as workstation, hub or switch and one fiber connection (multimode SC type connector) that allows connection to network devices equipped with 1000BaseSX interface or another GC-G21SC.