DEFINITY Enterprise Communications Server Release 8.2
Upgrades and Additions for R8r
555-233-115 Issue 1
April 2000
Glossary and Abbreviations

GL-27

inside call
A call placed from one telephone to another within the local communications system.
Integrated Services Digital Network (ISDN)
A public or private network that provides end-to-end dig ital communications for all services to
which users have access by a limited set of standard multipurpose user-network interfaces
defined by the CCITT. Through internationally accepted standard interfaces, ISDN provides digital
circuit-switched or packet-switched c ommunications within the network and links to other ISDNs to
provide national and international digital communications. See also Integrated Services Dig ital
Network Basic Rate Interface (ISDN-BRI) and Integrated Services Digital Network
Primary Rate Interface (ISDN-PRI).
Integrated Services Digital Network Basic Rate Interface (ISDN-BRI)
The interface between a communications system and terminal that includes two 64-kbps
B-channels for transmitting voice or data and one 16-kbps D-channel for transmitting associated
B-channel call control and out-of-band signaling information. ISDN-BRI also includes 48 kbps for
transmitting framing and D-channel contention information, for a total interface speed of 192 kbps.
ISDN-BRI serves ISDN terminals and digital terminals fitted with ISDN terminal adapters. See also
Integrated Services Digital Netwo rk (ISDN) andIntegrated Services Digital Net work
Primary Rate Interface (ISDN-PRI).
Integrated Services Digital Network Primary Rate Interface (ISDN-PRI)
The interface between multiple communications systems that in North America includes 24
64-kbps channels, corresponding to the North American d igital signal level-1 (DS1) standard rate
of 1.544 Mbps. The most common arrangement of channels in ISDN-PRI is 23 64-kbps B-channels
for transmitting voice and data and 1 64-kbps D-channel for transmitting associated B-c hannel call
control and out-of-band signaling information. With nonfacility-associated signaling (NFAS),
ISDN-PRI can include 24 B-channels and no D-channel. See alsoIntegrated Services Digital
Network (ISDN) andIntegrated Services Digital Network Ba sic Rate Interface (ISDN-BRI).
intercept tone
A tone that indicates a dialing error or denial of the service requested.
interface
A common boundary between two systems or pieces of equipment.
internal call
A connection between two users within a system.
International Telecommunications Union (ITU)
Formerly known as International Telegraph and Telephone Consultative Committee (CCITT), ITU is
an international organization that sets universal standards for data communications, including
ISDN. ITU members are from telecommunications companies and organizations around the world.
See also BX.25.
International Telegraph and Telephone Consultative Committee
See International Telecommunications Union (ITU).
interflow
The ability for calls to forward to other splits on the same PBX or a different PBX using the Call
Forward All Calls feature.
intraflow
The ability for calls to redirect to other splits on the same PBX on a conditional or unconditional
basis using call coverage busy, don’t answer, or all criteria.