ABSTRACT: This document replaces TA-NWT-000397 and TR-TSY-000397.

Integrated Services Digital Network (ISDN) is aimed at supporting an extensive menu of emerging and existing telecommunications services over an all-digital network. The transport systems used to provide access to this network will vary depending on the local environment. Services will be carried over two clear 64-kb/s B channels and a 16-kb/s D channel.

This Technical Reference (TR) presents the view of Telcordia on generic network equipment and interface requirements associated with the transport of ISDN Basic Access service capability through the telephone network. Most of the requirements deal with "Layer 1" issues, which address the transmission (transport) of information through physical media. The document provides the features for Basic Access transport over metallic loops, Digital Loop Carrier (DLC) systems, Digital Interoffice Carrier Systems (e.g., D-Banks and Automated Digital Terminal System [ADTS]), and other higher rate carrier systems. It also states requirements for systems that terminate ISDN Basic Access such as ISDN Switches, ISDN Remote Switch Units (RSUs), and stand-alone Exchange Terminations (ETs).