IP telephony (Internet Protocol telephony)
IP telephony (Internet Protocol telephony) is a general term for the technologies that use the Internet Protocol's packet-switched connections to exchange voice, fax, and other forms of information that have traditionally been carried over the dedicated circuit-switched connections of the public switched telephone network (PSTN).
IP telephony (Internet Protocol telephony) is a general term for the technologies that use the Internet Protocol's packet-switched connections to exchange voice, fax, and other forms of information that have traditionally been carried over the dedicated circuit-switched connections of the public switched telephone network (PSTN). Using the Internet, calls travel as packets of data on shared lines, avoiding the tolls of the PSTN. The challenge in IP telephony is to deliver the voice, fax, or video packets in a dependable flow to the user. Much of IP telephony focuses on that challenge.
IP telephone system
An IP telephone system uses packet-switched Voice over IP (VoIP), or Internet telephony, to transmit telephone calls over the Internet as opposed to the circuit-switched telephony used by the traditional Public Switched Telephone Network (PSTN). Also known as VoIP phone systems, IP telephone systems typically comprise a VoIP private branch exchange (an IP PBX) and desktop VoIP phones (IP Phones) that connect to a VoIP service provider via a Local Area Network (LAN).
One of the key advantages to IP telephone systems is that whereas long-distance calls on a regular phone system can be cost prohibitive, the same calls on an IP phone system are free -- there are no fees beyond the cost of Internet access.