The Link Between PSTN and VoIP

  Any system that relies on communication with others is powerfully impacted by what are known as "network effects". The more people using a particular system, the greater the network effects are. For example, if you're the only person in your circle of acquaintances who uses e-mail, it's almost useless to you since you can't send a message to anyone you know. On the other hand the more people you can communicate with via e-mail, the greater its value. Network effects tend to be self propagating - people join a communication system because others are already there. Facebook is a great example of a network whose primary value is derived from the large number of people participating in it.

smart voip is no exception to this rule. The more people you know who use VoIP, the greater its value becomes. But the overwhelmingly large percentage of people still use the traditional PSTN phone system. What use then for a smart voip communications technology that cannot make or receive calls to these individuals? The answer is not much use at all. Which is why it is so important for any smart voip network to be able to tap in to the PSTN phone system and make and receive calls. Without this functionality, no one would use it.

But the Internet and the traditional phone system are two completely different networks. The latter for example operates exclusively on telephone numbers. Depending on the protocol used, the Smart voip addressing system can use something like an SIP URI. As of now, it is Smart voip that has to accommodate itself to the older system due to the sheer number of people using the latter. Because of this, professional smart voip services issue their customers with a Direct Inward Dialing or DID number on which they can be reached and which shows on outgoing telephone calls.

The actual conversion of Internet traffic to analog signals and vice versa is performed at the Smart voip service provider's gateway. This is also the point where the majority of fees associated with smart voip are charged. After all, you've already paid for your Internet bandwidth - so it costs you nothing extra to send an e-mail to your friend. The telecom carriers however will charge you for every minute that you spend on their network.

So it is actually your smart voip provider who communicates with the older network and pipes the results to your smart voip client. This is how Smart voip links up with disparate communication networks. One day perhaps we can all do away with telephone numbers and talk to each other entirely over the Internet using SIP URI's. But till that time comes, and phone numbers will continue to dominate.