ITU Telecommunication Standardization Sector

One of the three Sectors (divisions or units) of the International Telecommunication Union (ITU).

The ITU Telecommunication Standardization Sector (ITU-T) coordinates standards for telecommunications and Information Communication Technology such as X.509 for cybersecurity, Y.3172 for machine learning, and H.264/MPEG-4 AVC for video compression, between its Member States, Private Sector Members, and Academia Members. ITU-T is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU).

The standardization efforts of ITU started in 1865 with the formation of the International Telegraph Union (ITU). ITU became a specialized agency of the United Nations in 1947. The International Telegraph and Telephone Consultative Committee (French: Comité Consultatif International Téléphonique et Télégraphique, CCITT) was created in 1956 and was renamed ITU-T in 1993.

ITU-T has a permanent secretariat, the Telecommunication Standardization Bureau (TSB), based at the ITU headquarters in Geneva, Switzerland. The current Director of the Bureau is Chaesub Lee, whose first 4-year term commenced on 1 January 2015, and whose second 4-year term commenced on 1 January 2019. Chaesub Lee succeeded Malcolm Johnson of the United Kingdom, who was director from 1 January 2007 until 31 December 2014.

The ITU-T mission is to ensure the efficient and timely production of standards covering all fields of telecommunications and Information Communication Technology (ICTs) on a worldwide basis, as well as defining tariff and accounting principles for international telecommunication services.

The international standards that are produced by the ITU-T are referred to as "Recommendations" (with the word capitalized to distinguish its meaning from the common parlance sense of the word "recommendation"), as they become mandatory only when adopted as part of national law.

Since the ITU-T is part of the ITU, which is a United Nations specialized agency, its standards carry more formal international weight than those of most other standards development organizations that publish technical specifications of a similar form.


At the initiative of Napoleon III, the French government invited international participants to a conference in Paris in 1865 to facilitate and regulate international telegraph services. A result of the conference was the founding of the forerunner of the modern ITU.

At the 1925 Paris conference, the ITU created two consultative committees to deal with the complexities of the international telephone services, known as CCIF, as the French acronym, and with long-distance telegraphy (CCIT).

In view of the basic similarity of many of the technical problems faced by the CCIF and CCIT, a decision was taken in 1956 to merge them into a single entity, the International Telegraph and Telephone Consultative Committee (CCITT, in the French acronym). The first Plenary Assembly of the new organization was held in Geneva, Switzerland in December 1956.

In 1992, the Plenipotentiary Conference (the top policy-making conference of ITU) saw a reform of ITU, giving the Union greater flexibility to adapt to an increasingly complex, interactive, and competitive environment. The CCITT was renamed the Telecommunication Standardization Sector (ITU-T), as one of three Sectors of the Union alongside the Radiocommunication Sector (ITU-R) and the Telecommunication Development Sector (ITU-D).

Historically, the Recommendations of the CCITT were presented at plenary assemblies for endorsement, held every four years, and the full set of Recommendations were published after each plenary assembly. However, the delays in producing texts, and translating them into other working languages, did not suit the fast pace of change in the telecommunications industry.

"Real-time" standardization

The rise of the personal computer industry in the early 1980s created a new common practice among both consumers and businesses of adopting "bleeding edge" communications technology even if it was not yet standardized. Thus, standards organizations had to put forth standards much faster, or find themselves ratifying de facto standards after the fact. One of the most prominent examples of this was the Open Document Architecture project, which began in 1985 when a profusion of software firms around the world was still furiously competing to shape the future of the electronic office and was completed in 1999 long after Microsoft Office's then-secret binary file formats had become established as the global de-facto standard.

The ITU-T now operates under much more streamlined processes. The time between an initial proposal of a draft document by a member company and the final approval of a full-status ITU-T Recommendation can now be as short as a few months (or less in some cases). This makes the standardization approval process in the ITU-T much more responsive to the needs of rapid technology development than in the ITU's historical past. New and updated Recommendations are published on an almost daily basis, and much of the library of over 3,270 Recommendations is now free of charge online. (Specifications jointly maintained by the ITU-T and ISO/IEC are not free.)

ITU-T has moreover tried to facilitate cooperation between the various forums and standard-developing organizations (SDOs). This collaboration is necessary to avoid duplication of work and the consequent risk of conflicting standards in the market place.

In the work of standardization, ITU-T cooperates with other SDOs, e.g., the International Organization for Standardization (ISO) and the Internet Engineering Task Force (IETF).

  • ITU-T
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