STAGE 3 DESCRIPTION FOR NUMBER IDENTIFICATION SUPPLEMENTARY SERVICES USING SIGNALLING SYSTEM No. 7 - CLAUSE 4 - CALLING LINE IDENTIFICATION RESTRICTION (CLIR) (Study Group XI)
FOREWORD The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the International Telecommunication Union. The ITU-T 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 World Telecommunication Standardization Conference (WTSC)@ which meets every four years@ established the topics for study by the ITU-T Study Groups which@ in their turn@ produce Recommendations on these topics. ITU-T Recommendation Q.731@ clauses 3@ 4@ 5 and 6@ was prepared by the ITU-T Study Group XI (1988-1993) and was approved by the WTSC (Helsinki@ March 1-12@ 1993).