ADTRAN ISU 512 user manual Isdn

Glossary

interface

A common boundary between two systems over which the inter-system commu- nication occurs.

ISDN

Integrated services digital network. A network architecture that enables end-to- end digital connections. The network supports diverse services through integrat- ed access arrangements and defines a limited set of standard, multipurpose inter- faces for equipment vendors, network providers, and customers. Interworking with a public switched telephone network is retained.

leased line

A telecommunication facility or link reserved for the exclusive use of one custom- er. Also called a dedicated line.

leased service

The exclusive use of any channel or combination of channels designated to a sub- scriber.

local loop

In telephony the wire pair that connects a subscriber to a phone company end of- fice, typically containing two wires. Four-wire local loops are common, however, especially with leased voice grade circuits.

loopback

A diagnostic procedure where data is sent to the device being tested, and the out- put of the device is fed directly back to its input, looped around, and the returning data is checked against that which was sent.

loopback test

A test typically run on a 4-wire circuit. Two transmit leads are joined to the two receive leads. A signal is then sent around the loop. Measuring differences be- tween the sent and received signal is the essence of a loopback test.

master clock

The source of timing signals, or the signals themselves, which all network stations use for synchronization.

message

The Layer 3 information that is passed between the CPE and SPCS for signaling.

multiplexing

The combining of multiple data channels onto a single transmission medium. Any process through which a circuit normally dedicated to a single user can be shared

102 ISU 512 User Manual 61202.086L1-1