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
ITU-T Q.542-1993 history
1993ITU-T Q.542-1993 Digital Exchange Design Objectives - Operations and Maintenance - Digital Exchanges (Study Group XI) 24 pp