AT&T Telephone DS1/DMi/ISDN-PRI Bedienungsanleitung PDF herunterladen (Seite 362)

GL-4 GLOSSARY

binary service One of two network specific facility (NSF) service types that are administered in

format conjunction with the Automatic Alternate Routing/Automatic Route Selection

(AAR/ARS) routing patterns. The binary service format conveys in a single

byte all the necessary information for the service or facility. See also

parameterized service format.

bipolar with 8-

An unrestricted or clear channel line-coding format that detects strings of eight

zero consecutive zeroes in the DS1’s signal and encodes these zeros (including framing

substitution

bits) into a unique bipolar pulse sequence that meets the ones-density

(B8ZS)

requirement. This sequence is detected and decoded at the receiver. Therefore,

digital data can be transmitted on these channels without concern about its

content.

bit error rate

A unit of measure indicating how successfully a digital signal is being

transmitted. Typically, bit error rate is expressed as a number of bit errors per

1,000 or 1,000,000 bits.

burstiness

BX.25

A network transmission impairment where the error burst is 10

-2

or worse and

often results in an out-of-frame condition. A single error burst of 2.5 seconds or

less will not generate an alarm.

An AT&T version of the CCITT X.25 protocol for data communications.

BX.25 adds a fourth level to the standard X.25 interface. This uppermost level

combines levels 4, 5, and 6 of the International Standards Organization (ISO)

reference model. See also CCITT, Flexible Assignment of BX.25 Signaling

Ports, packet switching, and X.25.

Call-by-Call

A feature that allows a communications system and/or service node to request,

(CBC) Service on a call-by-call basis, services and/or features for a particular call on an

Selection

Integrated Services Digital Network primary rate interface (ISDN-PRI) facility.

These services and/or features are selected with the call-setup message using

network-specific facilities, bearer capability, and destination-address information

elements (IEs). CBC allows various voice and data services, such as

MEGACOM

, Software-Defined Network (SDN), and ACCUNET

digital

service, to be integrated onto a single transmission facility with flexible

assignment of trunks to services.

CCITT

CCSA

CDM

(Comitée Consultatif International Telephonique et Telegraphique) an

international body that sets universal standards for data communications,

including Integrated Services Digital Network (ISDN). CCITT members are

from telecommunications companies and organizations around the world. See

also BX.25 and Q recommendations.

See Common-Control Switching Arrangement.

See channel-division multiplexer.

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