The Interference (ISI) introduced by the cable

The SFP+ interface offers the highest density, lowest cost, and lowest power 10 Gigabit Ethernet solution commercially available today. Further SFP+ Cables mass migration of the 1GbE network to 10 GbE by offering a very low cost 10GSFP+Cu (direct attached copper cable assembly) option for short reach interconnects along with multimode and single mode fiber options. The SFP+ interface accepts along with hot-pluggable, small-footprint, optical transceivers, a Direct Attach Cable “10GSFP+Cu”, which replaces two optical modules and a connectorized optical fiber with a twinaxial copper cable assembly. The 10GSFP+Cu option is defined for 10GbE applications over passive copper with a reach of  8.5m. The 10GSFP+Cu link utilizes a receive equalizer in the host PHY/SerDes in order to compensatefor the Inter Symbol Interference (ISI) introduced by the Twinax copper cable. Electrical and mechanical specifications for SFP+ Cables optical modules, 10GSFP+Cu, and hosts are defined in the SFF-8431 specification developed by the SFF Committee, with broad industry participation. These Direct Attach copper cable assemblies were the focus of the interoperability testing.