The ITU Telecommunication Standardization Sector (ITU-T) coordinates standards for telecommunications on behalf of the International Telecommunication Union (ITU) and is based in Geneva, Switzerland. Prior to 1992, it was known as the International Telegraph and Telephone Consultative Committee (CCITT, from the French name "Comité consultatif international téléphonique et télégraphique"). Standardization, in the context related to technologies and industries, is the process of establishing a technical standard among competing entities in a market, where this will bring benefits without hurting competition. ... Monument in Bern, Switzerland. ... 1992 (MCMXCII) was a leap year starting on Wednesday. ...

Primary function

The international standards that are produced by the ITU-T are referred to as "Recommendations" (with the word ordinarily capitalized to distinguish its meaning from the ordinary sense of the word "recommendation"). Since the ITU-T is part of the ITU, which is a United Nations Organization (UNO), its standards carry more formal international recognition than those of most other organizations that publish technical specifications of a similar form. United Nations - Wikipedia, the free encyclopedia /**/ @import /skins-1. ...

The sector divides its work into categories that are each identified by a single letter, referred to as the "series" (see below), and Recommendations are numbered within each series, for example "V.90".

History

Historically from 1960 until the formation of ITU-T in 1992, the Recommendations of the CCITT were presented to four-yearly "plenary assemblies" for endorsement, and the full set of Recommendations were published after each plenary assembly, in a set of volumes titled collectively for the colour of their covers. For example the publication after the 1980 plenary session was the Yellow Book while that after 1984 was the Red Book. These publications were divided into "fascicles" of several hundred pages that could be bought separately. The four-year approval cycle made the CCITT a rather slow and deliberate organization. 1960 (MCMLX) was a leap year starting on Friday (link will take you to calendar). ... 1980 (MCMLXXX) was a leap year starting on Tuesday. ... 1984 (MCMLXXXIV) is a leap year starting on Sunday of the Gregorian calendar. ...

ITU reorganization 1970s-1990s

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. Unfortunately, like the International Organization for Standardization (ISO), CCITT was slow to adapt. The 1980s decade refers to the years from 1980 to 1989, inclusive. ... In computer science, bleeding edge is a term that refers to technology that is so new (and thus, presumably, not perfected) that the user is required to risk reductions in stability and productivity in order to use it. ... Logo of the International Organization for Standardization The International Organization for Standardization (ISO) is an international standard-setting body composed of representatives from national standards bodies. ...

In some cases, a hopeless hodgepodge of proprietary standards resulted, with no clear winner; this was and still is the case with color fax technology. Another phenomenon was that the general public sought standards from organizations which it perceived as more responsive or inclusive; these included informal non-governmental organizations like the Internet Engineering Task Force (IETF) or private consortia like the World Wide Web Consortium (W3C). The Internet Engineering Task Force (IETF) is charged with developing and promoting Internet standards, in particular, those of the TCP/IP protocol suite. ... The World Wide Web Consortium (W3C) is an international consortium where member organizations, a full-time staff, and the public, work together to develop standards for the World Wide Web. ...

ITU's "real time" standardization: 2000-Present

In response to the mess that previous ITU practices had created, 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.

Changes in ITU-T compliance practices

A standard that has been amended can (if desired) retain its designation so that, for example, in the mid-1980s, terminal equipment for connection to an X.25 (packet switched) network might need alternative modes of operation depending on whether the network implemented the 1980 (Yellow Book) or the 1984 (Red Book) version of the standard. However, it is now more common for older versions of a standard to simply be marked as "superseded" when a standard is revised, and features of prior versions are ordinarily kept unchanged within the specification as new enhancements are added in new versions.

A standard can be developed that extends or is complementary to an existing one rather than replacing it. Such a standard is sometimes designated by the suffix "bis" or "ter" added to the base standard name, for example "V.26bis" and "V.26ter".

Series and Recommendations

ITU-T issues Recommendations that have names like X.500, where X is the series and 500 is a serial number. X.500 is the set of ITU-T computer networking standards covering electronic directory services such as white pages, Knowbot and whois. ...

See Category:ITU-T recommendations.

Significant ITU-T series and Recommendations are:

• A - Organization of the work of ITU-T
• B - Means of expression: definitions, symbols, classification,
• C - General telecommunication statistics
• D - General tariff principles
• E - Overall network operation, telephone service, service operation and human factors
  • E.123 Notation for national and international telephone numbers
  • E.163 Numbering plan for the international telephone service
  • E.164 The international public telecommunication numbering plan
    • Supplement 2 - Number Portability
• F - Non-telephone telecommunication services
• G - Transmission systems and media, digital systems and networks
  • G.711 Audio compression (mu-law)
  • G.722 Audio compression (wideband)
  • G.722.1 Audio compression (wideband, lower bit rates)
  • G.722.2 Speech compression AMR-WB (wideband, lower bit rates)
  • G.723.1 Speech compression CELP
  • G.726 Audio compression ADPCM
  • G.728 Speech compression LD-CELP
  • G.729 Speech compression ACELP
  • G.992.1 ADSL (G.DMT)
  • G.992.2 ADSL (G.Lite)
  • G.992.3/4 ADSL2
  • G.992.5 ADSL2+
• H - Audiovisual and multimedia systems
  • H.223 Multiplexing protocol for low bit rate multimedia communication
  • H.225.0 Also known as RTP
  • H.261 Video compression standard, circa 1991
  • H.262 Video compression standard (common text with part 2 of MPEG-2), circa 1994
  • H.263 Video compression standard, circa 1995
  • H.263v2 (a.k.a. H.263+) Video compression standard, circa 1998
  • H.264 Video compression standard (technically aligned with MPEG-4 part 10), circa 2003
  • H.320 Narrow-band visual telephone systems and terminal equipment
  • H.323 Packet-based multimedia communications systems
    • Annex D - Real-time facsimile over H.323 systems
    • Annex G - Text conversation and Text SET
    • Annex J - Security for H.323 Annex F
    • Annex K - HTTP based service control transport channel in H.323
    • Annex M.1 - Tunnelling of signalling protocol (Qsig) in H.323
    • Annex M.2 - Tunnelling of signalling protocol (Isup) in H.323
  • H.324 Terminal for low bit-rate multimedia communication
  • H.332 H.323 extended for loosely coupled conferences
• I - Integrated services digital network (ISDN)
• J - Transmission of television, sound programme and other multimedia signals
• K - Protection against interference
• L - Construction, installation and protection of cables and other elements of outside plant
• M - TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits
• N - Maintenance: international sound programme and television transmission circuits
• O - Specifications of measuring equipment
• P - Telephone transmission quality, telephone installations, local line networks
• Q - Switching and signalling
  • Q.931 Is the layer 3 standard for ISDN signaling
• R - Telegraph transmission
• S - Telegraph services terminal equipment
• T - Terminals for telematic services
  • T.4 Group 3 Apparatus for Transmission (aka Group 3 faxes)
  • T.6 Facsimile Coding Schemes and Coding Control Functions for Group 4 Facsimile Apparatus. (aka Group 4 Compression)
  • T.30 Procedures for Document Facsimile Transmission. (T.30e defines colour faxing).
  • T.31 and T.32 Provide an interface between fax machines and data terminals.
  • T.411 - T.424 Comprise the Open Document Architecture (ODA and ODIF), a standardized document file format
• U - Telegraph switching
• V - Data communication over the telephone network
  • V.1 Equivalence between binary notation symbols and the significant conditions of a two-condition code.
  • V.5 Standard that synchronous data signalling rates should be 600, 1200, 2400, 4800 and 9600 bit/s, to within better than 0.01%.
  • V.10 A recommendation, first agreed in 1976, for unbalanced electrical circuits for data communication at up to 100 kbit/s.
  • V.11 A recommendation, first agreed in 1976, for balanced electrical circuits for data communication at up to 10 Mbit/s.
  • V.17 A fax protocol that uses TCM modulation at 12 and 14.4 kbit/s.
  • V.21 A recommendation for full-duplex communication between two analogue dial-up modems using AFSK modulation at 300 bauds to carry data at 300 bit/s.
  • V.22 A recommendation for full-duplex communication between two analogue dial-up modems using PSK modulation at 600 bauds to carry data at 1200 or 600 bit/s.
  • V.22bis An extension of V.22 using QAM modulation at 600 bauds to carry data at 2400 or 1200 bit/s, with fall-back to V.22 mode.
  • V.23 A recommendation for half-duplex communication between two analogue dial-up modems using FSK modulation at up to 600 or 1200 bauds to carry digital data at up to 600 or 1200 bit/s respectively. An optional 75 bauds reverse channel carries 75 bit/s.
  • V.24 A list of definitions for interchange circuits between data terminal equipment (DTE) and data circuit terminating equipment (DCE), first agreed in 1964. This is equivalent to a subset of EIA RS 232: for the electrical and physical details, see V.28 and others.
  • V.25 A recommendation, first agreed in 1968, for automatic calling and/or answering equipment on dial-up lines, using interchange circuits defined in V.24 specifically for parallel automatic calling. It includes procedures for disabling network echo cancellers and suppressors.
  • V.25bis An extension of V.25 using the serial interchange circuits defined in V.24 for normal data transfer. Command formats are defined for asynchronous, and synchronous character- or bit-oriented (HDLC) operation.
  • V.26 A recommendation, first agreed in 1968, for full-duplex communication between two analogue fixed-line modems using PSK modulation at 1200 bauds to carry synchronous data at 2400 bit/s. An optional 75 bauds reverse channel carries 75 bit/s in either direction.
  • V.26bis An extension of V.26, first agreed in 1972, for half-duplex operation of dial-up modems, adding a fall-back rate of 1200 bit/s (still at 1200 bauds).
  • V.26ter An extension of V.26, first agreed in 1984, for full-duplex fixed-line or dial-up operation to carry synchronous or asynchronous data with a fall-back rate of 1200 bit/s (at 1200 bauds), separating channels by echo cancellation.
  • V.27 A recommendation, first agreed in 1972, for full-duplex or half-duplex communication between two analogue fixed-line modems using PSK modulation at 1600 bauds to carry synchronous data at 4800 bit/s. An optional 75 bauds reverse channel carries 75 bit/s.
  • V.27bis An extension of V.27, first agreed in 1976, adding a fall-back modulation rate, compatible with V.26, of 1200 bauds to carry data at 2400 bit/s. An adaptive equalizer is included to handle lower grade lines.
  • V.27ter An extension of V.27bis for use on dial-up lines.
  • V.28 A recommendation, first agreed in 1972, for unbalanced electrical circuits for data communication. Together with the circuit specifications of V.24 and the 25-pin connector and pin assignments of IS 2110, this is compatible with EIA RS 232.
  • V.29 A recommendation, first agreed in 1976, for full-duplex communication between two analogue fixed-line modems using QAM modulation at 2400 bauds to carry synchronous data at 9600 bit/s. Fallback rates of 7200 and 4800 bit/s use 2400 bauds at reduced modulations. Multiplexing of 7200, 4800 and 2400 bit/s subchannels up to an aggregate rate of 9600 bit/s is optional. An adaptation of this standard is used for facsimile (fax) transmission.
  • V.32 A recommendation, first agreed in 1984, for a family of duplex analogue dial-up or fixed-line modems using QAM modulation at 2400 bauds to carry data at 9600/4800/2400 bit/s.
  • V.32bis A duplex modem operating at data signalling rates of up to 14 400 bit/s for use on the general switched telephone network and on leased point-to-point 2-wire telephone-type circuits, with fallback to 12 kbit/s. This standard was improved on by modem manufacturers to create the V.terbo adhoc standard, signalling at 19,2 kbit/s, as suggestive of a V.32ter standard that never materialized.
  • V.34 is the ITU-T standard for full-duplex data communications up to 28,800 bit/s with fallback to lower speeds depending on the remote modem and the conditions of the phone line. This standard was known informally as V.Fast, hence pre-standard modems called V.FC (V.FastClass).
  • V.34bis A communications protocol for full-duplex datacommunications up to 33,6 kbit/s between two analog modems on dial-up lines.
  • V.42 Error correction protocol
  • V.42bis Data compression procedures for data circuit terminating equipment (DCE) using error correction procedures to try to ensure the transfer of error-free data, even over the noisiest telephone lines. Ratified by CCITT in January 1990.
  • V.44 Data compression protocol
  • V.90 A digital modem and analogue modem pair for use on the Public Switched Telephone Network (PSTN) at data signalling rates of up to 56 000 bit/s downstream and up to 33 600 bit/s upstream, using PCM encoding downstream, and QAM encoding upstream. V.90 Mode 2 used PCM upstream as well. This standard was known informally as V.Last and some pre-standard modems indicate V.Last compatibility or upgradeability. Prior to the arrival of the standard, there were two competing industry standards for 56 kbit/s downstream signalling, X2 and K56flex. K56flex itself is a merged standard of K56 and 56flex.
  • V.92 A digital modem and analog modem pair for use on POTS at data signalling rates of up to 56 kbit/s downstream and up to 48 kbit/s upstream, using PCM encoding both ways, supporting Modem-on-Hold technology. This is a development of V.90 Mode 2.
• X - Data networks and open system communication
  • X.1 International user classes of service in, and categories of access to, public data networks and Integrated Services Digital Networks (ISDNs)
  • X.3 This is essentially a numbered list of terminal and comms setting attributes.
  • X.21 Interface between Data Terminal Equipment and Data Circuit-terminating Equipment for synchronous operation on public data networks
  • X.25 Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit
  • X.29 Defines the level 4 (or the Session Layer, in the ISO_protocols) for X.25 communications. Call establishment and X.3 parameter negotiation occurs via the X.29 protocol.
  • X.75 Interface between DCE units in a network. Essentially transport of X.25 messaging.
  • X.110 International routing principles and routing plan for public data networks
  • X.121 International numbering plan for public data networks. This can be seen as the specification for X.25 Addresses.
  • X.200 Information technology - Open Systems Interconnection - Basic Reference Model: The basic model
  • X.208 Specification of Abstract Syntax Notation One (ASN.1)
  • X.209 Specification of Basic Encoding Rules for Abstract Syntax Notation One (ASN.1)
  • X.400 Message handling services: Message handling system and service overview
  • X.500 Information technology - Open Systems Interconnection - The Directory: Overview of concepts, models and services Common text with ISO/IEC
  • X.509 Information technology - Open Systems Interconnection - The Directory: Public-key and attribute certificate frameworks
  • X.520 Information technology – Open Systems Interconnection – The Directory - Selected Attribute Types
  • X.521 Information technology – Open Systems Interconnection – The Directory - Selected Object Classes
  • X.700 Management framework for Open Systems Interconnection for CCITT applications
  • X.701 Information technology — Open Systems Interconnection — Systems management overview
  • X.800 Security architecture for Open Systems Interconnection for CCITT applications
• Y - Global information infrastructure and Internet protocol aspects
• Z - Languages and general software aspects for telecommunication systems

ITU-T Recommendation E.123, or the Notation for national and international telephone numbers Recommendation E.123 defines a standard way to write telephone numbers, e-mail addresses, and web addresses. ... E.163 was an ITU-T standard for describing telephone numbers for the public voice network (PSTN). ... This article needs to be cleaned up to conform to a higher standard of quality. ... G.711 is an ITU-T standard for audio companding. ... G.722 is a ITU-T standard wideband speech codec operating at 32-64 kbit/s. ... G.722. ... Adaptive Multi Rate - WideBand or AMR-WB is a speech coding standard developed after the AMR using same technology like ACELP. The codec provides excellent speech quality due to wider speech bandwidth of 50 - 7000 Hz compared to narrowband speech codecs which in general are optimized for POTS wireline quality... Adaptive Multi Rate - WideBand or AMR-WB is a speech coding standard developed after the AMR using same technology like ACELP. The codec provides excellent speech quality due to wider speech bandwidth of 50 - 7000 Hz compared to narrowband speech codecs which in general are optimized for POTS wireline quality... G.723. ... CELP stands for Code Excited Linear Prediction and is a speech coding algorithm described by the US Federal Standard FIPS 1016. ... G.726 is ITU-T speech codec operating at bit rates of 16-40 kbit/s. ... Pulse-code modulation (PCM) is a modulation technique. ... G.728 is a ITU-T standard for speech coding operating at 16 kbit/s. ... G.728 is a ITU-T standard for speech coding operating at 16 kbit/s. ... G.729 is an audio data compression algorithm for voice that compresses voice audio in chunks of 10 milliseconds. ... Algebraic Code Excited Linear Prediction or ACELP is a speech encoding algorithm where a limited set of pulses is distributed as excitation to linear prediction filter. ... In telecommunications, ITU G.992. ... Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional modem can provide. ... ADSL in Australia started off as ITU G.992. ... This is an ITU (International Telecommunication Union) standard, also referred to as, ADSL2. ... This is an ITU (International Telecommunication Union) standard, also referred to as ADSL2+. This extends the capability of basic ADSL by doubling the number of downstream bits. ... H.225. ... The Real-time Transport Protocol (or RTP) defines a standardized packet format for delivering audio and video over the Internet. ... H.261 is an 1990 ITU video coding standard originally designed for transmission over ISDN lines on which data rates are multiples of 64 kbit/s. ... H.262 is an ITU-T digital video coding standard. ... MPEG-2 (1994) is the designation for a group of coding standards for digital audio and video, agreed upon by MPEG (Moving Pictures Experts Group), and published as the ISO/IEC 13818 international standard. ... H.263 is a video codec designed by the ITU-T as a low-bitrate encoding solution for videoconferencing. ... H.263. ... H.264, or MPEG-4 Part 10, is a digital video codec standard, which is noted for achieving very high data compression. ... MPEG-4, introduced in late 1998, is the designation for a group of audio and video coding standards and related technology agreed upon by the ISO/IEC Moving Picture Experts Group (MPEG). ... H.320 is a umbrella recommendation by the ITU-T for running Multimedia (Audio/Video/Data) over ISDN based networks. ... H.323 is an umbrella recommendation from the ITU-T, that defines the protocols to provide audio-visual communication sessions on any packet network. ... HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ... H.324 is an ITU-T recomendation for voice, video and data transmission over regular analog phone lines. ... An ISDN Telephone Integrated Services Digital Network (ISDN) is a type of circuit switched telephone network system, designed to allow digital transmission of voice and data over ordinary telephone copper wires, resulting in better quality and higher speeds than available with analog systems. ... The Telecommunications Management Network is a protocol model defined by ITU-T for managing open systems in a communications network. ... The ITU-T Recommendation Q.931 is ISDNs connection control protocol, roughly comparable to TCP in the Internet Protocol stack. ... ISDN is also short for isosorbide dinitrate Integrated Services Digital Network (ISDN) is a type of circuit switched telephone network system, designed to allow digital (as opposed to analog) transmission of voice and data over ordinary telephone copper wires, resulting in better quality and higher speeds, than available with analog... Fax (short for facsimile - from Latin fac simile, make similar, i. ... Fax (short for facsimile - from Latin fac simile, make similar, i. ... The Open Document Architecture (or sometimes referred to as Office Document Architecture or just ODA) is a standard document file format created by the ITU-T to replace all proprietary document file formats. ... The Open Document Architecture (or sometimes referred to as Office Document Architecture or just ODA) is a standard document file format created by the ITU-T to replace all proprietary document file formats. ... A document file format is a binary file format for storing documents on a storage media, especially for use by computers. ... The term V1 can refer to: The V-1 flying bomb, the first modern cruise missile, developed by the German Luftwaffe during the Second World War Decision speed, where an aircraft pilot must opt to abort the take-off or continue the run for lift-off at V2 speed. ... V.10 is a ITU-T recommendation, first agreed in 1976, for unbalanced electrical circuits for data communication at up to 100 kbit/s. ... Unbalanced is the opposite of balanced. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... V.11 is an ITU-T recommendation, first agreed in 1976, for balanced electrical circuits for data communication at up to 10 Mbit/s. ... In telecommunication, a balanced line is a transmission line consisting of two conductors in the presence of ground, capable of being operated in such a way that when the voltages of the two conductors at all transverse planes are equal in magnitude and opposite in polarity with respect to ground... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... An ITU-T fax protocol that uses TCM modulation at 12 and 14. ... Fax (short for facsimile - from Latin fac simile, make similar, i. ... In computing, a protocol is a convention or standard that controls or enables the connection, communication, and data transfer between two computing endpoints. ... In telecommunication, trellis modulation (also known as trellis coded modulation, or simply TCM) is a modulation scheme which allows highly efficient transmission of information over band-limited channels such as telephone lines. ... Modulation is the process of varying a carrier signal, typically a sinusoidal signal, in order to use that signal to convey information. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... V.21 is an ITU-T recommendation for full-duplex communication between two analogue dial-up modems using audio frequency-shift keying modulation at 300 bauds to carry digital data at 300 bit/s. ... In telecommunications, duplex means two-way when referring to communications channels. ... For the Analog Science Fiction and Science Fact publication, see Astounding Magazine. ... A modem (a portmanteau word constructed from modulator and demodulator) is a device that modulates a carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... Audio frequency-shift keying (AFSK) is a modulation technique by which digital data is represented as changes in the frequency (pitch) of an audio tone, yielding an encoded signal suitable for transmission via radio or telephone. ... Modulation is the process of varying a carrier signal, typically a sinusoidal signal, in order to use that signal to convey information. ... In telecommunications and electronics, baud (pronounced ) is a measure of the signaling rate which is the number of changes to the transmission media per second in a modulated signal. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... The V-22 Osprey is a joint service, multi-mission aircraft with vertical take-off and landing (VTOL) capability. ... In telecommunications, duplex means two-way when referring to communications channels. ... For the Analog Science Fiction and Science Fact publication, see Astounding Magazine. ... A modem (a portmanteau word constructed from modulator and demodulator) is a device that modulates an analog carrier signal (sound), to encode digital information, and that also demodulates such a carrier signal to decode the transmitted information. ... Phase-shift keying (PSK) is a digital modulation scheme that conveys data by changing, or modulating, the phase of a reference signal (the carrier wave). ... Modulation is the process of varying a carrier signal, typically a sinusoidal signal, in order to use that signal to convey information. ... In telecommunications and electronics, baud (pronounced ) is a measure of the signaling rate which is the number of changes to the transmission media per second in a modulated signal. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... V.22 bis is an ITU-T recommendation extending V.22 with a faster rate using QAM modulation at 600 bauds to carry digital data at 2400 or 1200 bit/s. ... The V-22 Osprey is a joint service, multi-mission aircraft with vertical take-off and landing (VTOL) capability. ... Quadrature amplitude modulation (QAM) is a modulation scheme which conveys data by changing (modulating) the amplitude of two carrier waves. ... Modulation is the process of varying a carrier signal, typically a sinusoidal signal, in order to use that signal to convey information. ... In telecommunications and electronics, baud (pronounced ) is a measure of the signaling rate which is the number of changes to the transmission media per second in a modulated signal. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... V.23 is an ITU-T recommendation for half-duplex communication between two analogue dial-up modems using FSK modulation at up to 600 or 1200 bauds to carry digital data at up to 600 or 1200 bit/s respectively. ... In telecommunications, duplex means two-way when referring to communications channels. ... For the Analog Science Fiction and Science Fact publication, see Astounding Magazine. ... A modem (a portmanteau word constructed from modulator and demodulator) is a device that modulates an analog carrier signal (sound), to encode digital information, and that also demodulates such a carrier signal to decode the transmitted information. ... Frequency-shift keying (FSK) is a form of frequency modulation in which the modulating signal shifts the output frequency between predetermined values. ... Modulation is the process of varying a carrier signal, typically a sinusoidal signal, in order to use that signal to convey information. ... In telecommunications and electronics, baud (pronounced ) is a measure of the signaling rate which is the number of changes to the transmission media per second in a modulated signal. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... RS-232 (also referred to as EIA RS-232C or V.24) is a standard for serial binary data interchange between a DTE (Data terminal equipment) and a DCE (Data communication equipment). ... DTE: Abbreviation for data terminal equipment. ... The three-letter acronym DCE may stand for: Data Circuit-Terminating Equipment (DCE), also Data Communications Equipment (DCE) and Data Carrier Equipment (DCE). ... EIA may refer to the following: Electronic Industries Alliance Energy Information Administration Environmental Impact Assessment Enzyme-Linked Immunosorbent Assay Equity Indexed Annuity Exercise-induced anaphylaxis This is a disambiguation page, a list of pages that otherwise might share the same title. ... RS-232 (also referred to as EIA RS-232C or V.24) is a standard for serial binary data interchange between a DTE (Data terminal equipment) and a DCE (Data communication equipment). ... RS-232 (also referred to as EIA RS-232C or V.24) is a standard for serial binary data interchange between a DTE (Data terminal equipment) and a DCE (Data communication equipment). ... RS-232 (also referred to as EIA RS-232C or V.24) is a standard for serial binary data interchange between a DTE (Data terminal equipment) and a DCE (Data communication equipment). ... It has been suggested that the section HDLC from the article Measuring_data_throughput be merged into this article or section. ... In telecommunications, duplex means two-way when referring to communications channels. ... For the Analog Science Fiction and Science Fact publication, see Astounding Magazine. ... A modem (a portmanteau word constructed from modulator and demodulator) is a device that modulates a carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... Phase-shift keying (PSK) is a digital modulation scheme that conveys data by changing, or modulating, the phase of a reference signal (the carrier wave). ... Modulation is the process of varying a carrier signal, typically a sinusoidal signal, in order to use that signal to convey information. ... In telecommunications and electronics, baud (pronounced ) is a measure of the signaling rate which is the number of changes to the transmission media per second in a modulated signal. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... In telecommunications, duplex means two-way when referring to communications channels. ... A modem (a portmanteau word constructed from modulator and demodulator) is a device that modulates a carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... In telecommunications and electronics, baud (pronounced ) is a measure of the signaling rate which is the number of changes to the transmission media per second in a modulated signal. ... In telecommunications, duplex means two-way when referring to communications channels. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... In telecommunications and electronics, baud (pronounced ) is a measure of the signaling rate which is the number of changes to the transmission media per second in a modulated signal. ... In telecommunications, duplex means two-way when referring to communications channels. ... In telecommunications, duplex means two-way when referring to communications channels. ... For the Analog Science Fiction and Science Fact publication, see Astounding Magazine. ... A modem (a portmanteau word constructed from modulator and demodulator) is a device that modulates a carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... PSK can relate to: phase-shift keying a telecommuncations term, or; Pre-Shared Key as a method to set encryption keys in Wi-Fi Protected Access, a wireless security scheme. ... Modulation is the process of varying a carrier signal, typically a sinusoidal signal, in order to use that signal to convey information. ... In telecommunications and electronics, baud (pronounced ) is a measure of the signaling rate which is the number of changes to the transmission media per second in a modulated signal. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... In telecommunications and electronics, baud (pronounced ) is a measure of the signaling rate which is the number of changes to the transmission media per second in a modulated signal. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... Unbalanced is the opposite of balanced. ... RS-232 (also referred to as EIA RS-232C or V.24) is a standard for serial binary data interchange between a DTE (Data terminal equipment) and a DCE (Data communication equipment). ... EIA may refer to the following: Electronic Industries Alliance Energy Information Administration Environmental Impact Assessment Enzyme-Linked Immunosorbent Assay Equity Indexed Annuity Exercise-induced anaphylaxis This is a disambiguation page, a list of pages that otherwise might share the same title. ... RS-232 (also referred to as EIA RS-232C or V.24) is a standard for serial binary data interchange between a DTE (Data terminal equipment) and a DCE (Data communication equipment). ... In telecommunications, duplex means two-way when referring to communications channels. ... For the Analog Science Fiction and Science Fact publication, see Astounding Magazine. ... A modem (a portmanteau word constructed from modulator and demodulator) is a device that modulates a carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... Quadrature amplitude modulation (QAM) is a modulation scheme which conveys data by changing (modulating) the amplitude of two carrier waves. ... Modulation is the process of varying a carrier signal, typically a sinusoidal signal, in order to use that signal to convey information. ... In telecommunications and electronics, baud (pronounced ) is a measure of the signaling rate which is the number of changes to the transmission media per second in a modulated signal. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... V.32 is an ITU-T recommendation for a modem, allowing bidirectional data transfer at either 9. ... In telecommunications, duplex means two-way when referring to communications channels. ... For the Analog Science Fiction and Science Fact publication, see Astounding Magazine. ... A modem (a portmanteau word constructed from modulator and demodulator) is a device that modulates a carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... Quadrature amplitude modulation (QAM) is a modulation scheme which conveys data by changing (modulating) the amplitude of two carrier waves. ... Modulation is the process of varying a carrier signal, typically a sinusoidal signal, in order to use that signal to convey information. ... In telecommunications and electronics, baud (pronounced ) is a measure of the signaling rate which is the number of changes to the transmission media per second in a modulated signal. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... V.32 is an ITU-T recommendation for a modem, allowing bidirectional data transfer at either 9. ... V.34 is: The communication protocol from ITU for 28. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... Look up Remote in Wiktionary, the free dictionary A remote may mean: A remote control A remote broadcast As an adjective, anything which is distant or desolate. ... V.34 is: The communication protocol from ITU for 28. ... V. 42 is an error correction protocol promoted by the ITU-T, a technical standards group within the United Nations]. Its function is to allow the receiver to immediately request re-transmission of any lost data packets. ... V.42bis is an adaptive data compression standard in common use nowadays. ... The three-letter acronym DCE may stand for: Data Circuit-Terminating Equipment (DCE), also Data Communications Equipment (DCE) and Data Carrier Equipment (DCE). ... V.44 is an adaptive data compression standard incorporated into the v. ... V.90 is an ITU-T recommendation for a modem, allowing 56 kbit/s download and 33. ... The public switched telephone network (PSTN) is the concatenation of the worlds public circuit-switched telephone networks, in much the same way that the Internet is the concatenation of the worlds public IP-based packet-switched networks. ... PCM is an initialism which can have different meanings: Phase Change Material Pulse-code modulation, a way to digitally encode signals representing sound and their video counterparts Potential Cancer Marker Communist Party of Mexico Plug Compatible Manufacturer Power-train control module, a computer in a car which controls the car... QAM is a TLA that may stand for: Quadrature amplitude modulation Quality Assurance Management (qam. ... K56flex (originally called the K56Plus) was a modem chipset from Rockwell and Lucent that gave users the possibility of receiving data on ordinary phone lines at 56 kbit/s as opposed to the previous maximum of 33. ... V.92 is an ITU-T modem standard allowing near 56 kbit/s download and 48 kbit/s upload rates first presented in August 1999. ... Plain old telephone service, or POTS, are the services available from analogue telephones prior to the introduction of electronic telephone exchanges into the public switched telephone network. ... PCM is an initialism which can have different meanings: Phase Change Material Pulse-code modulation, a way to digitally encode signals representing sound and their video counterparts Potential Cancer Marker Communist Party of Mexico Plug Compatible Manufacturer Power-train control module, a computer in a car which controls the car... X.21 is a digital signaling interface recommended by ITU-T that includes specifications for DTE/DCE physical interface elements, alignment of call control characters and error checking, elements of the call control phase for circuit switching services, data transfer at up to 2 Mbit/s, and test loops. ... X.25 is an ITU-T standard protocol suite for WAN networks using the phone or ISDN system as the networking hardware. ... X.121 is the ITU-T address format of the X.25 protocol suite used as part of call setup to establish a switched virtual circuit between Public Data Networks (PDNs), connecting two network user addresses (NUAs). ... The Open Systems Interconnection Reference Model (OSI Model or OSI Reference Model for short) is a layered abstract description for communications and computer network protocol design, developed as part of the Open Systems Interconnect initiative. ... The Open Systems Interconnection (usually abbreviated to OSI) was a new effort in networking started in 1982 by the International Organization for Standardization (ISO), along with the ITU-T. Prior to OSI, networking was completely vendor-developed and proprietary, with protocol standards such as SNA and DECnet. ... In telecommunications and computer networking abstract syntax notation one (ASN.1) is a standard, flexible method that describes data structures for representing, encoding, transmitting, and decoding data. ... In telecommunications and computer networking abstract syntax notation one (ASN.1) is a standard, flexible method that describes data structures for representing, encoding, transmitting, and decoding data. ... Basic encoding rules (BER) are ASN.1 encoding rules for producing self-identifying and self-delimiting transfer syntax for data structures described in ASN.1 notations. ... In computing, X.400 is a OSI standard developed by the ITU-T (at the time the CCITT) and promulgated by ISO for the exchange of email (at the time called IPMs - Inter Personal Messages). ... X.500 is the set of ITU-T computer networking standards covering electronic directory services such as white pages, Knowbot and whois. ... In cryptography, X.509 is an ITU-T standard for public key infrastructure (PKI). ... In cryptography, a public key certificate (or identity certificate) is a certificate which uses a digital signature to bind together a public key with an identity — information such as the name of a person or an organization, their address, and so forth. ... The ITU Telecommunication Standardization Sector (ITU-T) coordinates standards for telecommunications on behalf of the International Telecommunication Union (ITU) and is based in Geneva, Switzerland. ...

See also

• Other specifications which are numbered similarly to ITU-T Recommendations, but are not products of the ITU-T, include:
  • X10 Interface between Home Automation devices
  • Electronic Data Interchange ANSI Standard
  • ITU-R Recommendations, such as M.1457

X10 is an industry standard for communication among devices used for home automation. ... Electronic Data Interchange (EDI) is the computer-to-computer exchange of structured information, by agreed message standards, from one computer application to another by electronic means and with a minimum of human intervention. ... The ITU Radiocommunication Sector (ITU-R) is a standards body subcommittee of the International Telecommunication Union (ITU) relating to radio communication. ...

External links

• http://www.itu.int/ITU-T/