TA NPL 000912 : ISSUE 1

This document describes the electrical interactions for telephone exchange service at the network interface between customer premises equipment and a BCC's network. A summary of the features of telephone exchange service is provided. Service features that may be available in conjunction with telephone exchange service are also described. The interface specifications are for the common tip and ring interface. Protocols are specified for loop-start supervision, ground-start supervision and loop reverse-battery supervision. References are provided for quantitative limits on the voltages and currents at the interface