The CCITT (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
ITU-T Q.767-1991 history
1991ITU-T Q.767-1991 Application of the ISDN User Part of CCITT Signalling System No. 7 for International ISDN Interconnections (Study Group XI) 274 pp