IEEE 802.3ak-2004 PDF
The scope of this project is to specify additions to and appropriate modifications of IEEE Std 802.3 as amended by IEEE Std 802.3ae-2002 (and any other approved amendment or corrigendum) to add a copper Physical Medium Dependent (PMD) option for 10 Gb/s operation, building upon the existing 10GBASE-X Physical Coding Sublayer (PCS) and 10 Gigabit Attachment Unit Interface (XAUI) specifications.
The purpose of this project is to provide a lower-cost option for interconnection of closely located equipment (within ~15m of cable), typically within a stack or between equipment racks within a room.
Amendment Standard – Superseded. This amendment to IEEE Std 802.3-2002 as amended by IEEE Std 802.3ae-2002, IEEE Std 802.3af-2003 and IEEE Std 802.3aj-2003 specifies a new physical layer medium dependent sublayer interface for 10Gb/s Ethernet. 10GBASE-CX4 specifies an equipment interconnect based on the 10 Gigabit Attachment Unit Interface (XAUI) for up to 15m of balanced shielded cabling.