scope:

This American National Standard describes types of terminating test lines and their operational functions, and provides numbering plan arrangements to access these capabilities for testing across interconnections in the public switched network. The capability outlined in this standard applies to both end user and network providers access to existing and proposed terminating test lines from originating, intermediate and terminating points in the network. This standard also describes access to terminating test lines for exchange carriers, interexchange carriers, and customer premises equipment, e.g. Private Business Exchange (PBX), Internet Service Providers, etc. This standard does not include originating control devices. General descriptions of test line types are included in this standard since they link specific test access to test lines that perform specific functions in a defined manner to ensure uniform operation across network interfaces.