HOW IT WORKS Internet phone service
Many different forms of Internet telephony exist. Some systems, such as Skype, are primarily designed to be used between two computers using proprietary software. Others, such as Vonage's service, allow anyone with a broadband connection to use their existing telephone hardware or their computer, if they want, to call any other phone in the world, whether that phone is on the same service or not. Finally, businesses can install local VoIP, in which their internal phone system uses their local network. Once these calls go outside the company, they may run over either the Internet or regular phone lines, depending on what the company prefers and pays for.
The one thing all VoIP solutions have in common is that they take your voice and convert it into data packets that are then routed over the Net just like e-mail. For calls to a standard telephone, the data call obviously has to connect to the public phone network at some point; Internet phone services provide this connection seamlessly.
In the most flexible form of VoIP, Internet technology replaces the connection between the telephone and the phone company. You plug an ordinary telephone into an adapter that connects to your broadband setup. Your call is routed over the Web to a VoIP service provider. This provider connects your calls to the telephone system. If the person you are calling is also a user of the same Internet calling system, the call will never touch the phone system at all.
PC-to-PC Internet phone
Free Internet phone systems such as Skype and FreeWorld Dialup can bypass the telephone system completely, allowing you to make free calls to other users within their respective networks. Some free networks have added services, such as Skype's Skypeout service, that let you call mobile and standard telephones for a metered fee.
In a medium or large office, the internal phone system can be Internet based. In this case, calls between extensions, and possibly between office buildings, run over a private data network. To reach the outside world, the company's Internet phone system can connect to the Internet, the regular phone system, or both.