ADTRAN ISU 2X64 user manual Isdn

Glossary

ISDN

Integrated service 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.

LATA

Local Access and Transport Area. One of 161 local telephone serving areas in the United States, generally encompassing the largest standard statistical metropoli- tan areas. Subdivisions established as a result of the AT&T divestiture that now distinguish local from long distance service. Circuits with both end-points within the LATA (intraLATA) are generally the sole responsibility of the local telephone company, while circuits that cross outside the LATA (interLATA) are passed on to an interexchange carrier.

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 signalling.

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 by multiple users. Typically, user data streams are interleaved on a bit or byte ba- sis (time division) or separated by different carrier frequencies (frequency divi- sion).

multipoint circuit

A circuit consisting of three or more stations connected directly electrically.

140 ISU 2x64 Dual Port ISDN Service Unit User Manual 61200051L1-1D