The PE-TBI pack provides a Ten-Bit Interface for the PE-MCXMAC which allows this 10/100/1000Mbps Ethernet MAC to be used with a 1000BASE-X SERDES. (The PE-MCXMAC is also available in the Mentor Graphics Inventra (TM) range of soft cores.) The PE-TBI also allows connection to a multi-speed G/MII PHY. When operating in SERDES mode, the PE-TBI converts the 8-bit GMII transmit stream produced by the PE-MCXMAC into the 10-bit symbols required by the 1000BASE-X SERDES. In the Receive direction, it decodes the received 10-bit symbols and converts them into 8-bit data for the PE-MCXMAC’s GMII interface