D-Link DFE-660TX Product Manual - Page 5

DFE-660TX Fast Ethernet PC Card User's Guide 100Base-FX (using two fiber-optic strands). The DFE-660TX provides half-duplex 100Base-TX operation (in Category 5 twisted-pair cable environments). It does not provide 100Base-T4 or 100Base-FX operation. To provide for traditional 10Mbps Ethernet operation in twisted-pair cable environments, the DFE-660TX also offers 10Mbps Ethernet operation, in full-duplex and half-duplex modes. The DFE-660TX's autonegotiation capability provides for automatic selection of the best operation mode. About Autonegotiation The basic idea of autonegotiation 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 gravelly−sounding 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 communication 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 phoneline 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. Introduction 3