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DEFINITY® Enterprise Communications Server Release 7
Console Operations
555-230-700
Issue 4
June 1999
Glossary and Abbreviations
76
I
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 digital 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 communications within the network and links to other ISDNs to
provide national and international digital communications. See also
Integrated Services Digital
Network 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 digital 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-channel 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 also
Integrated Services Digital
Network (ISDN) .
intercept tone
A tone that indicates a dialing error or denial of the service requested.
internal call
A connection between two users within a system.
ISDN trunk
A trunk administered for use with ISDN-PRI. Also called ISDN facility.
L
line
A transmission path between a communications system or CO switching system and a phone or
other terminal.
line appearance
See
appearance.
LWC
Leave Word Calling
M
multiappearance phone
A terminal equipped with several call-appearance buttons for the same extension, allowing the
user to handle more than one call on that same extension at the same time.