Voice over IP is still an emerging technology and that means it is still changing in many ways. And, yes, there are many different ways to use VoIP. These include:


Computer-to-computer: Two parties in different locations speak to one another as each sits at a computer. This kind of VoIP connection has existed almost as long as the internet itself. Usually, both sides of the connection are using a headphones and a microphone (though you can use a computer's built-in microphone and external speakers, this usually causes an echo as what comes out of the speakers gets fed right back into the mic and severely disrupts a conversation). Think of this kind of use of VoIP as a modern day version of two cans and a string.

Computer-to-phone: This kind of connection is pouplar among those who make a lot of international calls. There are a number of services that offer overseas calling for just pennies a minute. The way it works is that you use your computer (again, with headphones and a mic is preferred) to log into a server, which then uses a VoIP connection to a regular landline phone exchange abroad, which then connects you to the number you want to reach.

SIP-to-SIP: This method allows telephone calls between two parties while totally bypassing the standard landline telephone system. Each end of a SIP-to-SIP call can use a specialized SIP phone (from companies such as Granstream, and others), a regular handset connected to an internet telephony adaptor, or a computer running softphone software. Companies such as SIPPhonbe offer SIP-to-SIP service.

Phone-to-phone: This method allows the use of VoIP service to contact any other telephone number, even one on the traditional landline service. Companies like Packet8, VoicePulse and Vonage offer this service.