Thanks floppy, for coming here to this thread.
I installed VLC Media Player and wow.. the modem is now detected and attached to ttyUSB0. Don't know what made the difference.
Am able to connect using wvdial; connects successfully and gives the IP Address, Remote IP, Primary DNS and Secondary DNS. But, there are two major problems now:
1. Though connected, am unable to browser through internet. Even, the Apps ends with a network error. Browser could find nothing on the internet too.
2. Every time I reboot the machine, the /etc/wvdial.conf file goes missing.
Please help me to overcome these two issues.
Thank you!