This American National Standard describes types of termination test lines and their operational functions, and provides numbering plan arrangements to access these capabilities for testing across various links in the public switched network. This includes both end-user and network capabilities for accessing existing and proposed termination test lines from end and intermediate points in the network. This standard describes access to terminating test lines from exchange-carrier, interexchange-carriers, and customer premises equipment. These capabilities are limited to present technologies and do not preclude their use on network trunk connections performed by SS7 or some ISDN applications. This standard does not include origination control devices. General descriptions of test line type 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.