I am new to linux. I have just installed UBUNTU 5.10. I have cable internet provided by local ISP. I have bought a D-Link nic card with model no: DFE-520TX. It is detected by the system. Now, the problem is I do not know how to configure this card to access the internet. Do I need modem?

Yes. You need a cable modem which connects to an ethernet nic.
Talk to your ISP.

Is your cable modem going to be directly plugged into your D-Link card? If so, setting up Ubuntu to use DHCP, or automatically configure your ip settings will work with most cable internet providers. The option for that should be somewhere in the networking section.

You need to supply more information about your cable internet. Some cable companies provide internet service by providing a cable modem. There are a few that run a fiber cable to the home and there is a fiber router that is used instead that provides an ethernet port that you connect to your NIC.

They usually also provide two types of service. A residential service that supplies one dynamic IP address ( modem using DHCP ), and a residential service that supplies from 1 to 3 fixed IP addresses. If you have the latter and you only have one computer. If you want to share the internet connection to other computers, the best thing to do is to purchase a NAT router. This will supply a 4 or 8 port network switch, and the NAT functionality will serve as a firewall as well.

The first time you connect a new device to a cable modem, you need to requisition it. This may entail pointing your modem to a web interface in the modem, such as "http://192.168.1.1" or to the web site address of your ISP.
You usually then need to read the terms of service and click on an OK button.

For a cable modem with a dynamic address, you can simply elect to use DHCP to set up your network card. This will supply your card with an IP address, the ISP's DNS server addresses (aka nameservers) and the default gateway.

Thanks for help.
The ISP provides me a residential service. I asked with the ISP and got a reply that I do not need a modem. I have only one computer to connect to the internet so I do not need a private network. The ISP provides me my username and password for the connection and there are two IP addresses for nameservers.I had pppd installed. I do pppoeconf and it worked but I have to configure it everytime I reboot. In pppoeconf I chose to activate eth0 at boot time. Still, I have to write sudo pppoeconf in terminal and while pppoeconf is in progress, I have to deactivate the nic card and complete the pppoeconf.How can I get the connection enabled without deactivating the nic each time?

You can try to use the command pon dsl-provider to connect. That's how I start my connection in Ubuntu 6.06. If that brings up your connection and you can surf, you can make it permanent.

Thanks wim
Your suggestion worked well.