Short for Voice over Internet Protocol, VoIP describes the category of hardware and software that enables people to make telephone calls via the Internet. Voice signals are converted to packets of data, which are transmitted on shared, public lines, hence avoiding the tolls of the traditional, public-switched telephone network (PSTN).

VoIP applications can generally be used with a simple microphone and computer speakers, but IP telephones or VoIP boxes can also be used, providing an experience identical to normal telephoning. In the past year, the quality and reliability of VoIP technology has improved to the point that vast numbers of users have abandoned their standard telephone contracts entirely, in favor of VoIP.