The IEEE 1000Base-KX interface is a GbE interface for backplane Ethernet specified by IEEE 802.3ap
. A point-to-point connection via the backplane is implemented via this interface. The connection is made over the traces of the backplane PCB. It can bridge a distance of 1 m and operates at a data rate of 1.25 GBaud. The interface operates with autonegotiation between the 1000Base-KX, 10GBase-KX4 and 10GBase-KR interfaces, with 8B/10B coding and with differential output levels of 800 mV and 1.6 V. Backplane Ethernet is particularly interesting for blade servers and backplane connections in other systems.