Specifies an enhancement to American National Standard for Information Technology - Fibre Channel - Physical and Signaling Interface (FC-PH), ANSI X3.240-1994, American National Standard for Information Technology - Fibre Channel - Physical and Signaling Interface-2 (FC-PH-2), ANSI X3.297-1997, and American National Standard for Information Technology - Fibre Channel - Physical and Signaling Interface-3 (FC-PH-3), ANSI X3.303-1998, and is an addendum to the FC-PH, FC-PH-2, and FC-PH-3 documents.