Lucent Technologies 8.2 User Manual

Issue 1

April 2000

Glossary and abbreviations 

1638

 

ISDN Network Service

A call placed from one telephone to another within the local communications system. 

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 com-
munications within the network and links to other ISDNs to provide national and international digital commu-
nications. See also 

Integrated Services Digital Network Basic Rate Interface (ISDN-BRI)

 and 

Integrated 

Services Digital Network Primary Rate Interface (ISDN-PRI)

.

The interface between a communications system and terminal that includes two 64-kbps B-channels for trans-
mitting 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 Network (ISDN)

 and

Inte-

grated Services Digital Network Primary Rate Interface (ISDN-PRI)

.

The interface between multiple communications systems that in North America includes 24 64-kbps chan-
nels, 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 informa-
tion. With nonfacility-associated signaling (NFAS), ISDN-PRI can include 24 B-channels and no D-channel. 
See also

Integrated Services Digital Network (ISDN)

 and

Integrated Services Digital Network Basic Rate 

Interface (ISDN-BRI)

.

A tone that indicates a dialing error or denial of the service requested.

A common boundary between two systems or pieces of equipment.

A connection between two users within a system.

Formerly known as International Telegraph and Telephone Consultative Committee (CCITT), ITU is an inter-
national 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

.

See 

International Telecommunications Union (ITU)

.

The ability for calls to forward to other splits on the same PBX or a different PBX using the Call Forward All 
Calls feature.

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.

BCMS measurements that are made by the system. ACD measurements that are made external to the system 
(via External CMS) are referred to as external measurements.