CCITT Languages for SPC Switching Systems

CCITT is one of the two consultative committees of the International Telecommunications Union. This paper describes in a general manner the procedures adopted by the CCITT in the process of developing standards for telegraphy and telephony. These standards are known as CCITT Recommendations. In particular, it covers the development, status and prospects of the CCITT Recommendations for three languages which have been developed for stored program controlled switching systems. The three languages are the specification and description language (SDL), the high-level programming language (CHILL), and the man-machine language (MML).