AT&T 2500 series Network Router User Manual


 
GL-8 GLOSSARY
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data communications
interface unit (DCIU)
An interface between the System 85 main processor (501CC) and AUDIX
equipment, or (in a DCS configuration) other switches. The DCIU
consists of four circuit packs in the System 85 and Generic 2 common
control carrier. System 75 and Generic 1 has a switched communication
interface (SCI) or processor interface (PI) to provide similar functionality.
data module A device that interfaces customer-provided data equipment with the
communications system via DCP or BRI protocols.
data path The end-to-end connection used for a data-communications link.
data protection A feature that prevents intrusions into data transmissions by using bridge-
on features, such as Call Waiting, Override, and Busy Verification of
Lines. The bridge-on features, if allowed, would disrupt a data
transmission by inserting a warning tone into the connection. Two forms
of Data Protection are available: temporary and permanent. Temporary
data protection is activated with an access code and permanent data
protection is assigned to a line class of service (COS).
data rate See bit rate.
data service unit (DSU) A device designed to transmit digital data on transmission facilities. See
also network channel-terminating equipment.
data signal level 1 (DS1) A 1.544 Mbps transmission facility.
data terminal An I/O device that has either switched or direct access to a host computer.
data terminal equipment
(DTE)
The equipment that makes up the endpoints in a connection over a data
circuit.
DCIU See data communications interface unit.
DCIU link A hardware communications link that connects two data-communications
interface units (DCIUs).
DCP See digital communications protocol.
DCS See distributed communications system.
DCS cluster Two or more communications systems interconnected by data
communications interface units (DCIUs) or switch
communications/processor interfaces (SCIs/PIs) and using distributed
communications system (DCS) software to provide transparency for a
limited set of station/attendant features. See also DCS Centralized
AUDIX, DCS endpoint, and DCS node.
DCS node A communications system within a distributed communications system
(DCS) cluster. See also DCS cluster.