AT&T DS1/DMi/ISDN-PRI Clock reference, See Integrated Services Digital Network, GL-12GLOSSARY

GL-12GLOSSARY

IntegratedThe interface between multiple communications systems that in North America

Services Digital includes 24 64K-bps channels, corresponding to the North American digital

Networksignal level 1 (DS1) standard rate of 1.544M-bps. The most common

primary rate arrangement of channels in ISDN-PRI is 23 64K-bps B-channels for transmitting

interfacevoice and data and 1 64K-bps D-channel for transmitting associated B-channel

(ISDN-PRI)call-control and out-of-band signaling information — an arrangement called 23B+lD, although with nonfacility-associated signaling (NFAS) ISDN-PRI can include 24 B-channels and no D-channel. See also 24th-channel signaling,

Integrated Services Digital Network, Integrated Services Digital Network basic rate interface, nonfacility-associated signaling, and out-of-band signaling.

interexchange The telecommunications company providing inter-LATA (local access and

carrier (IXC) transport area) public network transmission, such as AT&T, MCI, or Sprint. See also ISDN network identifier.

interface A common boundary between two systems or pieces of equipment.

internal clock The internal high-accuracy clock reference used by switching nodes within a

referenceprivate network to maintain proper network synchronization. See also external

clock reference.

interworking The linking of dissimilar networks to provide end-to-end call or feature processing.

ISDN See Integrated Services Digital Network.

ISDN dynamic The trunk type that permits a transmission facility to be used for a variety of

trunkdifferent trunk types on a call-by-call basis. A dynamic trunk differs from the more conventional, fixed-usage arrangement where each transmission facility is only associated with a single trunk type.

ISDN network A 3-digit field in a call-detail record that identifies a tariffed public-network

identifierservice such as WATS, MEGACOM® , and the Software-Defined Network (SDN), requested for a call. The INS value field is necessary to accommodate Call-by-Call (CBC) Service Selection in an Integrated Services Digital Network (ISDN), which allows a communications system to request services and/or features on a per-call basis. Also called ISDN network-service value.

ISDN network- See ISDN network identifier. service value