10gbase-cx4 Definition

An IEEE standard for twinaxial cable patch cord assemblies in support of 10G Ethernet over distances of up to 50 feet.The standard specifies the same connectors used in 4X InfiniBand and the XAIU (10 Gigabit Attachment Unit Interface) specified in 802.3ae, spreading the 10 Gbps datastream over four paired transmitters and receivers, with each pair operating differentially over a thin twinaxial cable. As the 10 Gbps is spread over the twinax bundle, each cable supports a data rate of 2.5 Gbps over a 3.125 GHz channel with 8B10B coding.This approach requires four differential pairs in each direction, for a total of eight twinax cables per assembly. The tight operating tolerances require that the cable assemblies be factory-terminated. Also, and in consideration of the impact of resistance on signal attenuation, the diameter of the center conductors is sensitive to cable length. At a distance of 20 feet, the outside diameter a CX-4 cable is approximately the same as that of a Cat 5e cable. See also 8B/10B, InfiniBand, twinaxial cable, and XAUI.