The CCI" (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITU).CCITT is responsible for studying technical,operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis.The Plenary Assembly of CCITTwhich meets every four years,establishes the topics for study and approves Recommendations prepared by its Study Groups.The approval of Recommendations by the members of CCITT between Plenary Assemblies is covered by the procedure laid down in CCIlTResolution No.2 (Melbourne, 1988).Recommendation 1.252.2 was revised by Study Group I and was approved under the Resolution No.2 procedure on the 4th of August 1992.