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There are also some nifty benefits to having your calls transmitted over
Internet. For example, some VoIP service providers allow you to check your voicemail via your e-mail, while others allow you to attach voice messages to your e-mails. How VoIP Works
The current phone system relies on a reliable but largely inefficient method for connecting calls known as circuit switching. This technique, which has been used for over 100 years, means that when a call is made between two people a connection is maintained in both directions between callers for duration of call. This dual directional characteristic gives system name circuit.
If, for example, you made a 30-minute call circuit would be continuously open, and thus used, between two phones. Up until about 1960, this meant that every call had to have an actual dedicated wire connecting two phones. Thus a long distance call cost so much, because you were paying for pieces of copper wire to be connected all way from your phone to destination phone, and for that connection to remain constant throughout call. Today, however, your analog call is converted after leaving your house to a digital signal, where your call can be combined with many others on a single fiber optic cable. While this system is certainly an improvement over past copper wire system, it is still quite inefficient. This inefficiency is due in part to fact that telephone line can't distinguish between useful talking and unneeded silences. For example, in a typical conversation while one person is talking other person is listening. Thus current analog system uses roughly half its space sending useless messages like this silence. But there is also more information, even down to pauses in speech, which under a more efficient system can be effectively cut out rather than wasting circuit space. This idea of only transmitting noisy bits of a telephone call and saving a great deal on circuit space, is basis of Packet-Switching, alternative method to circuit switching that VoIP phone system uses.
Packet-Switching is same method that you use when you view a website. For example, as you read this website, your computer is not maintaining a constant connection to site, but rather making connections to send and receive information only on an as needed basis (such as when you click on a link). Just as this system allows transfer of information over Internet to work so quickly, so also does it work in VoIP system. While circuit switching maintains a constant and open connection, packet switching opens connections just long enough to send bits of data called packets from one computer to another. This allows network to send your call (in packets) along least congested and cheapest lines available, while also keeping your computer or IP phone, free to send and receive messages and calls with other computers. This way of sending information, not to mention data compression, makes amount of information which must be transmitted for every call at least 3-4 times less for VoIP than exact same call in a conventional telephone system. For this reason, VoIP is so much cheaper than conventional calling plans.
The Future of VoIP
While most analysts believe it will be at least a decade before companies and telephone providers make full switch to VoIP, potential for technology's use today is already quite astounding. A report by Forrester Research Group predicts that by end of 2006, nearly 5 million U.S. households will be using VoIP phone service. With savings and flexibility that technology already offers, and new advances just ahead on horizon, we can expect those numbers will only increase in future.
Rich McIver is a contributing writer for VoIP Now: Voice over IP News. Learn more at http://www.voipnow.org .
