IEEE 10GBase-KX4
The 10GbE interface 10GBase-KX4 is an interface for backplane Ethernet specified by IEEE 802.3ap. It is a 10 Gigabit interface for a point-to-point connection over the backplane PCB traces. The link can span a distance of one meter, it consists of four lanes and has a data rate of 3.125 GBaud.
The 10GBase-KX4 interface works with auto-negotiation between the 1000Base-KX and 10GBase-KRinterfaces. It has 8B/10B coding and a differential output level of 800 mV and 1.6 V.
Since known interconnect components are used in the interface, signal quality can suffer during transmission in the backplane and cause inter symbol interference( ISI), which increases at higher frequencies. To reduce inter-symbol interference, the IEEE 802.3ap standards group has co-standardized Electronic Dispersion Compensation( EDC) and a Feed-Forward Equalization (FFE) in 10GBase-KX4. Backplane Ethernet is particularly interesting for blade servers and backplane connections in other systems.