Foreword The information contained in this Foreword is not part of this American National Standard (ANS) and has not been processed in accordance with ANSI's requirements for an ANS. As such@ this Foreword may contain material that has not been subjected to public review or a consensus process. In addition@ it does not contain requirements necessary for conformance to the standard. Accredited Standards Committee T1@ Telecommunications serves the public through improved understanding between carriers@ customers@ and manufacturers. Technical Subcommittee T1E1 of Committee T1 develops telecommunications standards and technical reports related to interfaces for U.S. telecommunications networks; some of which are associated with other North American telecommunications networks. ANSI guidelines specify two categories of requirements: mandatory and recommendation. The mandatory requirements are designated by the word shall and recommendations by the word should. Where both a mandatory requirement and a recommendation are specified for the same criterion@ the recommendation represents a goal currently identifiable as having distinct compatibility or performance advantages.