Purpose and Scope Several TIA standards have been developed within TR45 that are based upon ANSI/TIA/EIA-553. Since these new standards will evolve independently@ there will be changes made in the definition of message field assignments within the various messages. Since these standards are also dual mode (common analog)@ it is required that the interpretation of message fields be consistent for backward (and forward) compatibility. In order to facilitate this assessment of consistency@ this Technical Service Bulletin has been created. It is envisioned that this document be revised accordingly each time a new revision of the associated standards is officially published by TIA. The scope of this effort shall encompass all TIA TR45 Mobile Station - Land (Base) Station Compatibility specifications (commonly referred to as Air Interface specifications) that specifically or implicitly require interoperability. At this time@ the standards included herein are: ANSI/TIA/EIA-553@ ANSI/TIA/EIA-553-A@ EIA/TIA IS-54-B@ ANSI/TIA/EIA-627@ ANSI/TIA/EIA-136-0 (also referred to as IS-136-A)@ ANSI/TIA/EIA-136-A@ EIA/TIA IS-88@ EIA/TIA IS-91@ EIA/TIA IS-91-A@ ANSI/TIA/EIA-691@ EIA/TIA IS-94@ EIA/TIA IS-95-A@ TIA/EIA-95-B@ EIA/TIA IS- 683 and EIA/TIA IS-683-A. The specific revision and publication dates of the standards are contained in Section 2. Specific directions concerning the information contained in the messaging references are contained in Section 3. Note: Word formats for Narrow Analog Voice Channels (Forward and Reverse) are not included.