Glossary

2B+D See BRI.

23B+D See PRI.

30B+D See PRI.

802.2IEEE Standards that govern the LLC within the Data Link layer of the OSI model. LLC frames carry user information between the nodes on a network and define the transmission of a frame between two stations. These standards are common across the various lower level standards within the Data Link and the Physical layers.

802.3IEEE Standards that govern the use of the CSMA/CD (Carrier Sense Multiple Access/Collision Detection) network access method used by Ethernet networks.

802.5IEEE Standards that govern the use of the token ring indicator and frame priority.

Adapter A device, usually a user interface card, that physically connects an end station to the network medium (for example, twisted pair, coaxial, fiber).

AIS (Alarm Indication Signal) PRI alarm, also known as Keep Alive or Blue signal. An unframed all-ones signal sent to maintain transmission continuity.

AMI (Alternate Mark Inversion) A method of digitally encoding data as electrical signals on a link.

ANSI (American National Standards Institute) An organization which coordinates, develops, and publishes standards used in the United States.

AT&T 5ESS The name of a central office switch manufactured by AT&T. These switches use Custom (proprietary) or National ISDN-1 (NI-1) software. ESS stands for Electronic Switching System.

Attenuation Signal power lost in a transmission medium as the signal travels from sender to receiver.

B8ZS (Bipolar with 8 Zeros Substitution) Α method of digitally encoding data on a link. A modified form of AMI used in the USA.

bandwidth Capacity for transmitting data through a given circuit. Generally, the greater the bandwidth, the more information can be sent through a circuit during a given amount of time.

iSPAN PRI PCI ISDN Users Guide

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