I

Integrated Services Digital Network (ISDN)

A completely digital telephone/telecommunications network for carrying voice, data, images, and video at high speed by sending digitally encoded signals at speeds of up to 144,000 bps on Basic Rate Interface (BRI-ISDN) lines and much higher on Primary Rate Interface (PRI-ISDN) lines. ISDN is composed of at least three channels and as many as 32 channels, for simultaneous, independently operated transmission of voice and data. See also Basic Rate Interface (BRI-ISDN), Primary Rate Interface (PRI-ISDN).

Interactive Voice Response (IVR) Application

A telephony application that leads a telephone caller through a hierarchy of menus, delivers voice responses, collects voice and data inputs, and performs other operations on behalf of the caller or the program sponsor. See also Web Telephony.

inverse multiplexing

The process whereby bandwidth enables a call to transmit more information at the same time in the same timeframe than information from a single signal transmitted over a single channel. This is accomplished by splitting a single high-speed channel into multiple signals, transmitting the multiple signals over multiple facilities operating at a lower rate than the original signal, and then recombining the separately transmitted portions into the original signal at the original rate. See also bandwidth.

IP Multicast

IP multicast is a scheme for sending the same data to several machines simultaneously. A network with multicast-aware routers enabled will be able to convey such information much more rapidly by sending packets just once between routers. For additional information, see About Rendezvous IP Telephony Conferencing.

ISDN

See Integrated Services Digital Network (ISDN).