According to the ATIS Telecom Glossary 2000 (An updated version of the Federal Standard 1037C standard) a NIU is a device that “performs interface functions, such as code conversion, protocol conversion, and buffering, required for communications to and from a network.” A network interface, also commonly referred to as a smart jack, is a device that serves as the demarcation point between the end user's inside wiring and local access carriers' facilities. According to the TR-73569 standard put forth by Bellsouth, an NIU must have these functions: