About Auto-Negotiation - D-Link DFE-690TXD User Manual

operation in twisted-pair cable environments, the DFE-690TXD also offers
10Mbps Ethernet operation, in full-duplex and half-duplex modes. The DFE-
690TXD's auto-negotiation capability provides for automatic selection of the
best operation mode.

About Auto-negotiation

The basic idea of auto-negotiation can be understood by reflecting for a
moment on the familiar process of making a dialup connection between two
modems. You have probably heard some exchanges between your local modem
and a modem at the other end of a telephone line. (These exchanges are
ordinarily played out through a speaker in your local modem). As irritating as
those few seconds of noise may be, they do let you know that your modem and
the remote modem are on the job, preparing for your intended communication
with the remote computer.
The preparatory work of the two modems during those few seconds before you
see the "connect" message is to negotiate the best data communicatio n scheme
which is supported by both modems, and which is suitable for the quality of the
telephone- line connection between them. The parameters to be settled between
the two modems include best baud rate, compression method, and error
correction method. When the two modems have tested the phone- line quality
and have switched to the combination of parameters which will provide the
best data communication, then you are given the "connect" message which
signals the end of the inter- modem negotiation and the beginning of your
intended communication with the remote computer.
Auto-negotiation between devices within an Ethernet LAN is similar in
concept, but much briefer. The two devices involved in the auto-negotiation
will be your DFE-690TXD and the switch or hub through which it is connected
into the LAN. (Switches ordinarily provide for auto-negotiation; traditional
hubs do not.) The parameters to be negotiated between the DFE-690TXD and
- 4 -