Capacity The ultimate limitation of any resource in a network to hold or
move information.
Cathode Ray Tube (CRT)
Used in a generic sense to refer to data terminals that display
transmitted and received information on a television-like screen.
CCS Traffic usage measurement equating to 100 call seconds.
CDX Compact Digital Exchange.
Channel A single, physical communications medium capable of moving
intelligence from one point to another. Specific physical or
logical and electrical parameters generally define its capacity.
Also see group or link.
CMP Communication Module Processor.
CNI Common Node Interface.
Coder/Decoder (CODEC)
The device that turns analog signals into digital signals and
vice-versa.
Communications Module 2 (CM2)
The DRM’s fully duplicated time multiplexed switch which acts
as a distribution hub for calls and control signals.
Concentration The effect of having more inputs than outputs for a given
system.
CORC Customer Originated Recent Change.
CU Control Unit.
Customer-Originated Recent Changes (CORC)
A customer-controlled database change caused by a change in
the lines, trunks, equipment, and/or features associated with
telephone numbers of a particular telephone office.
DAT Tape Drive Digital Audio magnetic tape format device for permanent
storage of information.
Data Circuit Terminating Equipment
The network side of the user/network (DCE) interface. The
CCITT recommendation X.25 specifies the interface between
data circuit terminating equipment and data terminal
equipment.
Data Link A communication path directly connecting two entities. Also an
ensemble of terminal installations and the interconnecting
network operating in a particular mode that permits
information to be exchanged between terminal installations.
Data Link Protocol Guarantees error-free communication between two devices by
ensuring that sender and receiver agree on initialization, error
detection, and recovery procedures.
Dataphone
4
Digital Service
Service that provides for direct connection of digital sources to a
communications medium and, thereby, to each other.
4. Registered trademark of AT&T Corp.
235-200-150
May 2003
GLOSSARY
Issue 3.00 Page G-3
To Next Page