A category of hardware and software that enables people to use the Internet rather than the traditional telephone to transmit voice or fax. In other words, it adds telephone capabilities to a PC. For users who have free or fixed-price Internet access, Internet telephony software essentially provides free telephone calls anywhere in the world. Although it generally does not yet offer the same sound quality as direct telephone connections, it does over broadband connections.
The term "telephony" refers to the science of translating sound into electrical signals, transmitting them, and then converting them back to sound-in other words, the science of telephones. Telephony software can also combine with your modem to turn your computer into an answering service. Voice mail is another popular telephony application.