PC-to-PC

• PC-to-PC VoIP systems make phone calls from a computer to another computer. This system requires that both computers have the same software installed. Other requirements include a microphone to be able to speak into and speakers to hear the conversation. In most cases, the software is free and the calls completed are free. Some service providers that offer PC-to-PC VoIP systems include Skype, Windows Live Messenger from Microsoft, Yahoo! Messenger and Google Talk.
  
  

PC-to-Phone

• In PC-to-phone VoIP systems the call is placed from the computer directly to a traditional phone. These systems require a download of software and a calling plan. Users can select local and long distance services and may be provided a separate phone number for these types of systems. A "softphone," which dials phone numbers using the computer software, is the common way of dialing and completing PC-to-phone calls.
  
  

IP-Phone-to-Phone

• A special type of telephone commonly called an IP or broadband phone is connected directly through the broadband connection. An IP phone will be able to complete all the functions of a traditional phone systems such as hold, transfer and conference. Many businesses use IP phone systems to connect workers across the country into a single virtual office, with each worker having an extension from the primary phone number no matter the his location.
  
  

Advantages of VoIP

• There are a number of advantages to VoIP systems compared to traditional phone systems. In the PC-to-PC calling system, the calls are free no matter the distance as long as both individuals have the software downloaded on each PC. Other VoIP systems can reduce cost by eliminating the need for traditional phone line service, utilizing the broadband connection. The service plan costs tend to be lower than traditional phone services due to the amount of competition in the VoIP market, according to the VoIP Review website.