The CCITT (the International Telegraph and Telephone Consultative Committee) is a perinanent organ of
the Iiiteniational Telecomnunication Union (ITU). CCITT is responsible for studying technical, operating atid tariff questions and issuing Recommendatio
ITU-T E.424-1992 history
1992ITU-T E.424-1992 Test Calls - Telephone Network and ISDN Quality of Service Network Management and Traffic Engineering (Study Group II) 5 pp