ISDN (Integrated Services Digital Network): Numbering, addressing and interworking

The factors that affect the design of a numbering plan for the Integrated Services Digital Network (ISDN) involved a complex interplay between existing plans, national priorities, and technical system limitations. These factors are the subject of the report. Desirable attributes of any numbering plan are explained, existing standards covering various plans are discussed and some actual plans currently in use are examined. The development of the numbering plan for ISDN by the Consultative Committee for International Telegraph and Telephone is essentially complete.