The steps to be followed are as under:
1. edit /etc/wvdial.conf in your favourite text editor and make these changes:
Init1 = AT+CGDCONT=1,"IP","airtelgprs.com"
Modem Type = USB Modem
Phone = *99#
Password = pass
Username = user
Modem = /dev/ttyACM0
Baud = 460800
2. In the 2'nd line Init1 shows the initialization string for your phone. airtelgprs.com will be the acceess point of you are using Airtel GPRS. For other carriers kindly contact your Internet Service Providor. The second last option Modem is the USB device, which may be traced by supplying the command dmesg | grep "ACM"
3. issue the command # wvdial and note down the DNS addressses. Now just disconnect by pressing Ctrl + C or somthing similar.
4. now some extra tweakings, despite doing these changes I was unable to browse the Internet, and heuristic worked here:
edit the file /etc/resolv.conf and append it with obtained Name servers, something like this:
5. Now it is almost ready to surf, just open a console and issue command # wvdial
6. Open Firefox and go to File -> Uncheck on Work Offilne option.
Now it is ready to!