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The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the
International Telecommunication Union The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Unio ...
(ITU). It is responsible for coordinating standards for
telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that ...
and Information Communication Technology such as
X.509 In cryptography, X.509 is an International Telecommunication Union (ITU) standard defining the format of public key certificates. X.509 certificates are used in many Internet protocols, including TLS/SSL, which is the basis for HTTPS, the secu ...
for cybersecurity,
Y.3172 Y.3172 is an ITU-T Recommendation specifying an architecture for machine learning in future networks including 5G (IMT-2020). The architecture describes a machine learning pipeline in the context of telecommunication networks that involves the t ...
and Y.3173 for machine learning, and H.264/MPEG-4 AVC for video compression, between its Member States, Private Sector Members, and Academia Members. The first meeting of the
World Telecommunication Standardization Assembly The World Telecommunication Standardization Assembly (WTSA) is the governing conference of the ITU Standardization Sector (ITU-T), one of the three world conferences of the International Telecommunication Union, and as such, the United Nations ...
(WTSA), the sector's governing conference, took place on 1 March of that year. ITU-T has a permanent secretariat called the Telecommunication Standardization Bureau (TSB), which is based at the ITU headquarters in Geneva, Switzerland. The current director of the TSB is Chaesub Lee (of
South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...
), 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 The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and ...
, who was director from 1 January 2007 until 31 December 2014.


Primary function

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 a 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.


History

At the initiative of
Napoleon III Napoleon III (Charles Louis Napoléon Bonaparte; 20 April 18089 January 1873) was the first President of France (as Louis-Napoléon Bonaparte) from 1848 to 1852 and the last monarch of France as Emperor of the French from 1852 to 1870. A neph ...
, 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 The ITU Radiocommunication Sector (ITU-R) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU) and is responsible for radio communications. Its role is to manage the international radio-frequency ...
) and the Telecommunication Development Sector (
ITU-D The ITU Telecommunication Development Sector (ITU-D) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU); it is responsible for creating policies, regulation and providing training programs and financi ...
). 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 A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or te ...
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 were still furiously competing to shape the future of the electronic office, and was completed in 1999 long after
Microsoft Office Microsoft Office, or simply Office, is the former name of a family of client software, server software, and services developed by Microsoft. It was first announced by Bill Gates on August 1, 1988, at COMDEX in Las Vegas. Initially a marketin ...
'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 nearly all of the library of over 3,270 Recommendations is now free of charge online. (About 30 specifications jointly maintained by the ITU-T and ISO/IEC are not available for free to the public.) 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 The International Organization for Standardization (ISO ) is an international standard development organization composed of representatives from the national standards organizations of member countries. Membership requirements are given in A ...
(ISO) and the
Internet Engineering Task Force The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements an ...
(IETF).


Development of Recommendations

Most of the work of ITU-T is carried out by its Sector Members and Associates, while the Telecommunication Standardization Bureau (TSB) is the executive arm of ITU-T and coordinator for a number of workshops and seminars to progress existing work areas and explore new ones. The events cover a wide array of topics in the field of information and communication technologies (ICT) and attract high-ranking experts as speakers, and attendees from engineers to high-level management from all industry sectors. The technical work, the development of Recommendations, of ITU-T is managed by Study Groups (SGs), such as Study Group 13 for network standards, Study Group 16 for multimedia standards, and
Study Group 17 Study or studies may refer to: General * Education ** Higher education * Clinical trial * Experiment * Observational study * Research * Study skills, abilities and approaches applied to learning Other * Study (art), a drawing or series of draw ...
for security standards, which are created by the
World Telecommunication Standardization Assembly The World Telecommunication Standardization Assembly (WTSA) is the governing conference of the ITU Standardization Sector (ITU-T), one of the three world conferences of the International Telecommunication Union, and as such, the United Nations ...
(WTSA) which is held every four years. As part of the deliberations, WTSA has instructed ITU to hold the Global Standards Symposium, which unlike WTSA is open to public for participation. The people involved in these SGs are experts in telecommunications from all over the world. There are currently 11 SGs. Study groups meet face to face (or virtually under exceptional circumstances) according to a calendar issued by the TSB. SGs are augmented by Focus Groups (FGs), an instrument created by ITU-T, providing a way to quickly react to ICT standardization needs and allowing great flexibility in terms of participation and working methods. The key difference between SGs and FGs is that the latter have greater freedom to organize and finance themselves, and to involve non-members in their work, but they do not have the authority to approve Recommendations. Focus Groups can be created very quickly, are usually short-lived and can choose their own working methods, leadership, financing, and types of deliverables. Current Focus Groups include the
ITU-WHO Focus Group on Artificial Intelligence for Health The ITU-WHO Focus Group on Artificial Intelligence for Health (AI for Health) is an inter-agency collaboration between the World Health Organization and the ITU, which created a benchmarking framework to assess the accuracy of AI in health. Thi ...
(FG-AI4H) as well as Machine Learning for 5G (which developed
Y.3172 Y.3172 is an ITU-T Recommendation specifying an architecture for machine learning in future networks including 5G (IMT-2020). The architecture describes a machine learning pipeline in the context of telecommunication networks that involves the t ...
), Quantum Information Technologies for Networks, and Artificial Intelligence for Assisted and Autonomous Driving.


Alternative Approval Process

The Alternative Approval Process (AAP) is a fast-track approval procedure that was developed to allow standards to be brought to market in the timeframe that industry now demands. The AAP is defined in ITU-T Recommendation A.8. This dramatic overhaul of standards-making by streamlining approval procedures was implemented in 2001 and is estimated to have cut the time involved in this critical aspect of the standardization process by 80 to 90 percent. This means that an average standard that took around four years to approve and publish until the mid nineties, and two years until 1997, can now be approved in an average of two months, or as little as five weeks. Besides streamlining the underlying procedures involved in the approval process, an important contributory factor to the use of AAP is electronic document handling. Once the approval process has begun the rest of the process can be completed electronically, in the vast majority of cases, with no further physical meetings. The introduction of AAP also formalizes public/private partnership in the approval process by providing equal opportunities for both sector members and member states in the approval of technical standards. A panel of SG experts drafts a proposal that is then forwarded at an SG meeting to the appropriate body which decides if it is sufficiently ready to be designated a draft text and thus gives its consent for further review at the next level. After this Consent has been given, TSB announces the start of the AAP procedure by posting the draft text to the ITU-T website and calling for comments. This gives the opportunity for all members to review the text. This phase, called ''last call'', is a four-week period in which comments can be submitted by member states and sector members. If no comments other than editorial corrections are received, the Recommendation is considered approved since no issues were identified that might need any further work. However, if there are any comments, the SG chairman, in consultation with TSB, sets up a comment resolution process by the concerned experts. The revised text is then posted on the web for an ''additional review'' period of three weeks. Similar to the last call phase, in ''additional review'' the Recommendation is considered as approved if no comments are received. If comments are received, it is apparent that there are some issues that still need more work, and the draft text and all comments are sent to the next Study Group meeting for further discussion and possible approval. Those Recommendations considered as having policy or regulatory implications are approved through what is known as the Traditional Approval Process (TAP), which allows a longer period for reflection and commenting by member states. TAP Recommendations are also translated into the six working languages of ITU (Arabic, Chinese, English, French, Russian, and Spanish).


Series and Recommendations

ITU-T Recommendations are the names given to telecommunications and computer protocol specification documents published by ITU-T.


Recommendation categorization

ITU-T assigns each Recommendation a name based on the series and Recommendation number. The name starts with the letter of the series the Recommendation belongs to. Each series encompasses a broad category of Recommendations, such as "H-Series Recommendations: Audiovisual and multimedia systems". The series letter is followed by a period and the Recommendation number, which uniquely identifies the Recommendation within the series. Often, a range of related Recommendations are further grouped within the series and given adjacent numbers, such as "H.200-H.499: Infrastructure of audiovisual services" or "H.260-H.279: Coding of moving video". Many numbers are "skipped" to give room for future Recommendations to be adjacent to related Recommendations. Recommendations can be revised or "superseded" and keep their existing Recommendation number.


Key standards published by ITU

*
ASN.1 Abstract Syntax Notation One (ASN.1) is a standard interface description language for defining data structures that can be serialized and deserialized in a cross-platform way. It is broadly used in telecommunications and computer networking, and ...
(Abstract Syntax Notation One) * Coding of audio: G.711 and G.72x series * Coding of still images:
JPEG JPEG ( ) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and imag ...
T.8x, JPEG 2000 T.80x and JPEG XR T.83x series * Coding of video:
H.120 H.120 was the first digital video compression standard. It was developed by COST 211 and published by the CCITT (now the ITU-T) in 1984, with a revision in 1988 that included contributions proposed by other organizations. The video turned out not ...
, H.261, H.262 (MPEG-2 Video),
H.263 H.263 is a video compression standard originally designed as a low-bit-rate compressed format for videotelephony. It was standardized by the ITU-T Video Coding Experts Group (VCEG) in a project ending in 1995/1996. It is a member of the H.26x fam ...
, H.264 (MPEG-4 AVC), H.265 (HEVC),
H.266 Versatile Video Coding (VVC), also known as H.266, ISO/IEC 23090-3, and MPEG-I Part 3, is a video compression standard finalized on 6 July 2020, by the Joint Video Experts Team (JVET), a joint video expert team of the VCEG working group of ITU-T ...
(VVC) * Construction, installation and protection of cables and other elements of outside plant, L-series *
Data communication Data transmission and data reception or, more broadly, data communication or digital communications is the transfer and reception of data in the form of a digital bitstream or a digitized analog signal transmitted over a point-to-point or p ...
over the telephone network, V-series * Fax standards T.2 – T.4, T.30,
T.37 T.37 is an ITU standard which deals with sending fax messages using email. It is also referred to as "Internet fax" or "Store-forward-fax". A fax machine supporting T.37 will send a fax to an email address by converting the document to a TIFF-F ...
,
T.38 T.38 is an ITU recommendation for allowing transmission of fax over IP networks (FoIP) in real time. History The T.38 fax relay standard was devised in 1998 as a way to permit faxes to be transported across IP networks between existing Group 3 ...
*
F.780.2 Accessibility of telehealth services or F.780.2 is a technical standard developed by the World Health Organization and ITU ( Study Group 16) that defines accessibility requirements for technical features to be used and implemented by government ...
* G.114 is an
ITU The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Union ...
Recommendation that addresses acceptable delays for voice applications, is oriented to national telecommunications, and is more stringent than what is normally applied in private voice networks. One of the issues it addresses is voice delay. It states that 150 milliseconds is acceptable, while 400 milliseconds is unacceptable. * G.191: Software tools for speech and audio coding standardization * G.651.1 Multi-mode optical fiber (MMF) * G.652, G.655,
G.657 G.657 is an international standard developed by the Standardization Sector of the International Telecommunication Union (ITU-T) that specifies single-mode optical fiber (SMF) cable. History The G.657 Recommendation builds on a previous fiber ...
Single-mode optical fiber (SMF) * G.8201 Error performance parameters and objectives for multi-operator international paths within optical transport networks *
G.hn G.hn is a specification for home networking with data rates up to 2 Gbit/s and operation over four types of legacy wires: telephone wiring, coaxial cables, power lines and plastic optical fiber. A single G.hn semiconductor device is able to n ...
(Next generation wired home networking over powerlines, phonelines and coaxial cable) * Green ICT standards and supplements (L.1000 series) *
H.323 H.323 is a recommendation from the ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network. The H.323 standard addresses call signaling and control, mu ...
family of standards for multimedia and VoIP *
H.870 H.870 "Guidelines for safe listening devices/systems" (formerly F.SLD) is an ITU-T Recommendation, developed in collaboration with the World Health Organization. It specifies standards for safe listening to prevent hearing loss and was first appr ...
safe listening standard (audio) developed together with the
World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level o ...
* Interconnection rate harmonization, D-series * International Emergency Preference Scheme E.106 * International telecommunication charge card
E.118 E.118 is an international standard that defines the international telecommunication charge card, for use in payphones, it also defines the Integrated Circuit Card Identifier (ICCID), which is used in SIM cards, including eSIM cards. The standard ...
* IMSI codes used in SIM cards
E.212 The international mobile subscriber identity (IMSI) is a number that uniquely identifies every user of a cellular network. It is stored as a field and is sent by the mobile device to the network. It is also used for acquiring other details of th ...
* ISDN and PSTN/ 3G videoconferencing systems, H.320 and
H.324 H.324 is an ITU-T recommendation for voice, video and data transmission over regular analog phone lines. It uses a regular 33,600 bit/s modem for transmission, the H.263 codec for video encoding and G.723.1 for audio. H.324 standard is formal ...
* ISDN (Integrated Services Digital Network)
Q.931 ITU-T Recommendation Q.931 is the ITU standard ISDN connection control signalling protocol, forming part of ''Digital Subscriber Signalling System No. 1''. Unlike connectionless systems like UDP, ISDN is connection oriented and uses explicit si ...
*Objective voice quality measurements P.861, P.862, P.863 *
Open Systems Interconnection The Open Systems Interconnection model (OSI model) is a conceptual model that 'provides a common basis for the coordination of SOstandards development for the purpose of systems interconnection'. In the OSI reference model, the communications ...
* Optical Transport Network (OTN) G.709, G.798, G.872 * Passive optical networks (PON)
G.983 ITU-T Recommendation G.983 is a family of recommendations that defines broadband passive optical network (BPON) for telecommunications Access networks. It originally comprised ten recommendations, G.983.1 through G.983.10, but recommendations .6 ...
, G.984, G.987 * Public key infrastructure (PKI)
X.509 In cryptography, X.509 is an International Telecommunication Union (ITU) standard defining the format of public key certificates. X.509 certificates are used in many Internet protocols, including TLS/SSL, which is the basis for HTTPS, the secu ...
* Public telecommunication numbering plan, E.164 * Security framework X.805 * Signalling System 7 Q.7xx series * Standards relating to quality of service (QoS) and quality of experience (QoE) * Specification and Description Language *
Synchronous Digital Hierarchy Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diodes ...
(SDH) G.707, G.783, G.803 * T.192, Cooperative document handling *
TrustworthyAI Trustworthy AI is a programme of work of the ITU (United Nations Specialized Agency for ICT) under its AI for Good programme. The programme advances the standardization of a number of Privacy-enhancing technologies (PETs), including homomorphic ...
* Wavelength-division multiplexing (WDM) *
X.25 X.25 is an ITU-T standard protocol suite for packet-switched data communication in wide area networks (WAN). It was originally defined by the International Telegraph and Telephone Consultative Committee (CCITT, now ITU-T) in a series of drafts a ...
, packet switching *
X.400 X.400 is a suite of ITU-T Recommendations that defines the ITU-T Message Handling System (MHS). At one time, the designers of X.400 were expecting it to be the predominant form of email, but this role has been taken by the SMTP-based Internet e- ...
email * Y.3800 Quantum Key Distribution * (x) DSL (Digital Subscriber Line) series of standards for broadband telecoms * G.8013/Y.1731 Operations, administration and maintenance (OAM) functions and mechanisms for Ethernet-based networks * Machine Learning for 5G and future networks (IMT2020): **
Y.3172 Y.3172 is an ITU-T Recommendation specifying an architecture for machine learning in future networks including 5G (IMT-2020). The architecture describes a machine learning pipeline in the context of telecommunication networks that involves the t ...
** Y.3173 ** Y.3176 ** Y.3181


International Telecommunication Regulations (ITRs)

In addition to the ITU-T Recommendations, which have non-mandatory status unless they are adopted in national laws, ITU-T is also the custodian of a binding international treaty, the International Telecommunication Regulations. The ITRs go back to the earliest days of the ITU when there were two separate treaties, dealing with telegraph and telephone. The ITRs were adopted, as a single treaty, at the World Administrative Telegraphy and Telephone Conference held in Melbourne, 1988 (WATTC-88). The ITRs comprise ten articles which deal, '' inter alia'', with the definition of international telecommunication services, cooperation between countries and national administrations, safety of life and priority of telecommunications and charging and accounting principles. The adoption of the ITRs in 1988 is often taken as the start of the wider liberalization process in international telecommunications, though a few countries, including United States and United Kingdom, had made steps to liberalize their markets before 1988. The Constitution and Convention of ITU provides for the amendment of ITRs through a World Conference on International Telecommunications (WCIT). Accordingly, in 1998 there began a process of review of the ITRs; and in 2009 extensive preparations began for such a conference, WCIT-12. In addition to "regional preparatory meetings," the ITU Secretariat developed 13 "Background Briefs on key issues" that were expected to be discussed at the conference. Convened by former ITU secretary-general Hamadoun Touré, the Conference, WCIT-12, was then held in Dubai, United Arab Emirates, during the period 3–14 December 2014.


AI for Good

The Standardization Sector of ITU also organizes AI for Good, the United Nations platform for the sustainable development of Artificial Intelligence.


Hot topics

* ITU-T has expressed a commitment to "bridging the standardization gap" – disparities in the ability of developing countries, relative to developed ones, to access, implement, contribute to and influence international ICT standards. * The ICT Security Standards Roadmap has been developed to assist in the development of security standards by bringing together information about existing standards and current standards work in key standards development organizations. * The
Next Generation Networks The next-generation network (NGN) is a body of key architectural changes in telecommunication core and access networks. The general idea behind the NGN is that one network transports all information and services (voice, data, and all sorts of med ...
(NGN) concept takes into consideration new realities in the telecommunication industry characterized by factors such as; the need to converge and optimize the operating networks and the extraordinary expansion of digital traffic (i.e., increasing demand for new multimedia services, mobility, etc.). *


See also

*
ITU Radio Regulations The ITU Radio Regulations (short: RR) is a basic document of the International Telecommunication Union (ITU) that regulates on law of nations scale radiocommunication services and the utilisation of radio frequencies. It is the supplementatio ...
*
Global Standards Collaboration The Global Standards Collaboration (GSC) started life as The "Inter-regional Telecommunications Standards conference (ITSC) in 1990. This was an initiative of the T1 Committee of the United States who invited the other founding partner organization ...
*
ITU-R recommendations The ITU Radiocommunication Sector (ITU-R) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU) and is responsible for radio communications. Its role is to manage the international radio-frequency s ...
* ITU-T recommendations * World Summit on the Information Society * World Standards Day


References


External links

*
ITU-T Recommendations
{{DEFAULTSORT:Itu-T Standards Sector