I recently procured an ADSL modem for use with my BSNL broadband connection, and had some anxious moments trying to configure some configuration parameters to make it connect successfully to the Internet. So, thought of sharing like parameters here. Well, here they are:

 Virtual Circuit PVC0 
Status Activated
VCI 35
ISP/Connection Type Bridge Mode
Encapsulation LLC

Of these, the most important setting probably is for the VPI/VCI and Connection Type. After googling, I found suggestions for specifying PPPoA/PPPoE as the value for this parameter, but take care that this value is for MTNL, and not BSNL. For BSNL, Connection Type/ISP has to be Bridge Mode.

For reference, I am attaching 2 images below, one for Beetle, and the other for D-Link modems that should also provide some help.

Beetle Modem ADSL configuration for BSNL   D-Link modem configuration for BSNL broadband