(ITU) ITU-T, the telecommunication standardisation sector of ITU, is responsible for making technical recommendations about telephone and data (including fax) communications systems for PTTs and suppliers. Before 1993-03-01 ITU-T was known as CCITT. Every four years they hold plenary sessions where they adopt new standards; there was one in 1992. ITU works closely with all standards organisations to form an international uniform standards system for communication. Study Group XVII is responsible for recommending standards for data communications over telephone networks. They publish the V.XX standards and X.n protocols. V.21 is the same as EIA's EIA-232. V.24 is the same as EIA's EIA-232C. V.28 is the same as EIA's EIA-232D.