ADTRAN Express 6120 Manual de Instruções descarregar pdf (Página 143)

Glossary

61200176L1-1 Express 6100/6120 User Manual Glossary-3

ofvariedfrequenciesaswithtraditionalanalogtransmissionsystems.

Digital techniques provide more efficient use of transmission facili-

ties, resulting in lower error rates and costs than analog systems.

digital hub

Designated office where DDS channels are interconnected and where

synchronous network timing, testing access, and additional service

features are provided.

Ethernet

A local area network used for connecting computers, printers, work-

stations, a terminals, servers, etc., within the same building or cam-

pus. Ethernet operates over twisted wire and coaxial cable at speeds

up to 10 Mbps. Ethernet specifies a CSMA/CD.

four-wire circuits

Telephonelines using twowiresfor transmittingandtwowiresforre-

ceiving, offering much higher quality than a 2-wire circuit. All long

distance circuits are 4-wire. Almost all localphone lines and analog

phones are 2-wire.

group 4

A high-speed (56 kbps) facsimile protocol specific to ISDN.

hop count

A routing metric used to measure the distance between a source and

a destination. Particularly used by RIP.

hub

(1) Communications center, (2) Major routing station for connecting

channels, (3) DDS connecting center.

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ADTRAN Express 6120 Manual de Instruções Página 143