The Physical Coding Sublayer (PCS) for 1000BASE-X operation is defined in IEEE 802.3-2008, clauses 36 and 37, and performs these operations:
- Encoding (and decoding) of GMII data octets to form a sequence of ordered sets
- 8B/10B encoding (and decoding) of the sequence ordered sets
- 1000BASE-X or 2500BASE-X Auto-Negotiation for information exchange with the link partner
- 2500BASE-X PCS operation is similar to 1000BASE-X operation as defined in IEEE 802.3-2008, clauses 36 and 37