S = PCI - copper

EF = PCI express - fibre
PF = PCI express - fibre
ET = PCI express - copper
PT = PCI express - copper

XF = PCI-X - fibre
MF = PCI-X - fibre
MT = PCI-X - copper
GT = PCI-X - copper

http://forum.pfsense.org/index.php?topic=23934.0

http://communities.intel.com/message/11472#11472

http://www.intel.com/support/network/sb/cs-009221.htm