The fully integrated Physical Coding Sublayer (PCS), KR FEC (IEEE Clause 74 – fire code FEC), SGMII / 1000BASE-X and Media Access Controller (MAC) core for 25Gbps, 10Gbps, 2.5Gbps/1.25Gbps Ethernet applications is compliant with IEEE 802.3 standard and SGMII specification. The interface to the PMA supports a single channel Quad-mode bi-directional, serial interface. The PCS sublayer supports both 64/66B encoding (10GE) and 8B10B encoding (SGMII/1000BASE-X) with an optional FEC layer function for backplane (10G-KR) application. This Quad-Mode Core is configurable through software register.