Acronyms and Definitions

A VoIP protocol that preceeded SIP. Unlike SIP, the H.323 standard specifies the complete voice over IP protocol, and not just the signalling methods.

Integrated Access Device . All-in-one VoIP adapters that also include a router and possibly an ADSL modem are known as IADs.

Message Waiting Indication. Message Waiting Indication is a common feature of telephone networks. It typically involves an audible or visible indication that messages are waiting, such as playing a special dial tone (which in telephone networks is called message-waiting dial tone), lighting a light or indicator on the phone, displaying icons or text, or some combination.

Network Address Translator . Defined in RFC 1631, network address translation allows one public IP address to be shared between a number of devices. This is done by the device with the public address, acting as a gateway between an Internal network (running on private IP addresses - RFC 1918) and making all requests coming from the Internal network appear as though they are coming from the gateway device itself. It is commonly used in home networks.