The SGMII (Serial Gigabit Media Independent Interface) is a supplement of MII, a standard interface used to connect an Ethernet MAC-block to a PHY. It is utilised for Gigabit Ethernet (contrary to Ethernet 10/100 for MII). It differs from GMII by its low-power and low pin count serial interface (commonly referred to as a SerDes). To carry frame data and link rate information between a 10/100/1000 PHY and an Ethernet MAC, SGMII uses a differential pair for data signals and for clocking signals, with both being present in each direction (i.e., transmit and receive), giving 8 signal lines in total.