The Internet Protocol (IP) is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.
IP has the task of delivering packets from the source host to the destination host solely based on the IP addresses in the packet headers. For this purpose, IP defines packet structures that encapsulate the data to be delivered. It also defines addressing methods that are used to label the datagram with source and destination information.
Historically, IP was the connectionless datagram service in the original Transmission Control Program introduced by Vint Cerf and Bob Kahn in 1974; the other being the connection-oriented Transmission Control Protocol (TCP). The Internet protocol suite is therefore often referred to as TCP/IP.
Integrated Services Digital Network. A type of fast digital business grade telephone line. Early digital data technology superseded by ADSL due to cost. Still used by broadcasters to some extent, but dying out fast.
IVR (Interactive voice response) is a technology that allows a computer to interact with humans through the use of voice and DTMF tones input via keypad.