BSNL Dataone is an ISP in India (Government Owned). I had a D-Link 500T from one of my previous ISP and wanted to configure it for my BSNL Dataone Connection.
Lets assume that you have done the connections to the modem properly (the aDSL cable properly connected and an RJ45 Cable between your desktop and the modem, your LAN card to get IP from the modem using DHCP)
The following are the steps to configure it:
1. Login to your modem
2. Create a new connection, or edit the Connection 1 settings to look like the following:
Basically, the following are the settings:
Options: NAT and Firewall to be checked
Username: username@dataone (where username is what BSNL gave you)
Password: xxxxx (of course, the password that BSNL gave you)
Keep Alive: 10 mins
Max Fail: 10 Times
MTU: 1400 bytes
Set Router: Checked
On Demand: Not Checked
3. Save the settings and reboot the router. Check the connection from your desktop.