Ethernet; Automatic Negotiation - Sun Microsystems Ultra 80 Service Manual

rates greater than 100 Kbaud, the slew rate is increased to 10 VDC per microsecond.
This allows maximum performance for the greater baud rates and better signal
quality at the lesser baud rates.
C.1.11

Ethernet

The system supports 10-Mbps, 10BASE-T, twisted-pair Ethernet and 100-Mbps,
100BASE-T. Twisted-pair Ethernet is provided through an 8-pin RJ45 connector. The
Ethernet circuitry design is based on a Quality Semiconductor PHY.
The PHY chip integrates a 100BASE-T physical coding sub-layer (PCS) and a
complete 10BASE-T module in a single chip.
The 100BASE-X portion of the PHY IC consists of the following functional blocks:
Transmitter
Receiver
Clock generation module
Clock recovery module
The 10BASE-T section of the PHY IC consists of the 10-Mbps transceiver module
with filters.
The 100BASE-X and 10BASE-T sections share the following functional
characteristics:
PCS control
IEEE 802.3u auto negotiation
The following sections provide brief descriptions of the following:

Automatic negotiation

Connectors
C.1.11.1 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.
-26 Sun Ultra 80 Service Manual • March 2000