HI Sunil,
You are half right. I have the VOIP blaster http://www.innosphere.net/voipblaster/default.htm installed on both ends. So both the terminals has to be connected to the internet. I can call them on the phone but its not big diff in price then the normal call (to india). On the other hand they can call me on my phone for only about 10 A cents a min. I usually tops up there account from time to time. But the quality of the call is less then average.