Voice over Internet Protocol systems transmit phone calls over the Internet. Unlike traditional phone service, VoIP doesn't carry signals across the country on telephone lines, and works even in houses without phone wiring and just Internet access. There are two distinct types of VoIP, each offered by numerous competing carriers: VoIP programs that run on a computer, and VoIP services that connect your existing telephone to the Internet.
Computer-based VoIP services, including Skype and Google Hangouts, have instant messaging components, supporting free text chats and webcam chats between members. In addition to computer-to-computer connections, however, these programs can place and receive phone calls from regular telephones. Each company monetizes its service differently. For example, Skype permits unlimited calling between members on the computer, but calling regular phone lines requires a monthly subscription or incurs per-minute costs. Google Hangouts allows free calls to regular phones within the United States and Canada -- and incoming calls from phones, if you have a Google Voice number -- but charges for calls to other countries.
Home Phone VoIP
Landline-based VoIP services, such as those from Vonage, Ooma and many cable companies, are designed to replace home phone service from a phone company. These systems connect to any home telephone, allowing you to make and receive calls as usual on a traditional phone line. Most phone-based VoIP systems have a monthly subscription fee, but Ooma offers free calling within the United States, after the purchase of an adapter box. Other services usually offer adapters for free or for a monthly rental fee.
VoIP systems that connect to telephones don't require any special hardware, outside the adapter box sold or provided by the VoIP company. VoIP computer programs, on the other hand, require a computer headset or a microphone and pair of speakers. If you plan to use a computer-based VoIP system as your primary phone, you should buy a headset you're comfortable wearing for long periods of time. Whichever type of VoIP you pick, you need a high-speed Internet connection. This can make VoIP a poor home phone replacement for DSL Internet customers, as DSL itself often requires home phone service or costs more without it.
VoIP phone service won't work when your Internet goes down, and in the case of computer-based VoIP, you need to have your computer turned on to receive calls. VoIP also won't work during a power outage, unlike corded telephones, but cordless home phones suffer the same limitation. VoIP systems vary in compatibility when calling 911. Vonage, for example, supports enhanced 911, and can provide your location to emergency services, whereas Skype does not support 911 calls at all, and warns customers to avoid using the system as their sole phone line for this reason.