Avaya definity Operation Manual page 94

Glossary and Abbreviations
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
(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
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.
N
network
A series of points, nodes, or stations connected by communications channels.
88 DEFINITY ECS Console Operations
Integrated Services Digital Network Primary Rate Interface
(ISDN).