1. Su to root and enter run modprobe using the product and vendor ID of your cable model.

[helpero@localhost ~]$ su
Password:
[root@localhost helpero]# /sbin/modprobe usbserial vendor=vendorid(ex: 0x0421) product=productid(ex: 0x0802)

2. Now connect your phone to the PC via the cable.

3. Then run the command "wvdialconf create"

[root@localhost helpero]# wvdialconf create

It will scan the ports for modem. It should find a Nokia modem in one of the ports. In my case, it was detected in '/dev/ttyACM0'.

4. Now, open KPPP. Provide the root password when prompted.
Now create a new connection with the following Account details:

Name : Airtel (anything!)
Number : *99#
Authentication : script-based (select from list)

The rest of the Account settings you can keep as default.

Now click on the Modem tab and provide the following Modem details:

Name : Phone model (anything!)
Modem : /dev/ttyACM0 (in my case) (select from list)
Speed : 115200 (select from list)

Save it.

Now, from the KPPP main window, select our new connection and click on "CONNECT".

Thats it ! After "Modem Ready" and "Logging on to Network" messages displayed, KPPP will establish the connection and will minimize to the task bar.

Happy surfing!