C.1.10.1 Automatic Negotiation

Automatic negotiation controls the cable when a connection is established to a network device. It detects the various modes that exist in the linked partner and advertises its own abilities to automatically configure the highest performance mode of inter-operation, namely, 10BASE-T, 100BASE-TX, or 100BASE-T4 in half- and full-duplex modes.

The Ethernet port supports automatic negotiation. At power up, an on-board transceiver advertises 100BASE-TX in half-duplex mode, which is configured by the automatic negotiation to the highest common denominator based on the linked partner.