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A British football index page from October 2009, showing the three-digit page numbers for a variety of football news stories">Ceefax football index page from October 2009, showing the three-digit page numbers for a variety of football news stories
Teletext, or broadcast teletext, is a standard for displaying text and rudimentary graphics on suitably equipped
television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...
sets.
Teletext sends data in the broadcast signal, hidden in the invisible
vertical blanking interval
In a raster scan display, the vertical blanking interval (VBI), also known as the vertical interval or VBLANK, is the time between the end of the final visible line of a frame or field and the beginning of the first visible line of the next fra ...
area at the top and bottom of the screen. The teletext decoder in the television buffers this information as a series of "pages", each given a number. The user can display chosen pages using their
remote control
In electronics, a remote control (also known as a remote or clicker) is an electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operate devices such a ...
.
In broad terms, it can be considered as
Videotex
Videotex (or interactive videotex) was one of the earliest implementations of an end-user information system. From the late 1970s to early 2010s, it was used to deliver information (usually pages of text) to a user in computer-like format, typi ...
, a system for the delivery of information to a user in a computer-like format,
typically displayed on a television or a dumb terminal, but that designation is usually reserved for systems that provide bi-directional communication, such as
Prestel
Prestel (abbrev. from press telephone), the brand name for the UK Post Office Telecommunications's Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979. It achieved a maxim ...
or
Minitel
The Minitel was a videotex online service accessible through telephone lines, and was the world's most successful online service prior to the World Wide Web. It was invented in Cesson-Sévigné, near Rennes in Brittany, France.
The service w ...
.
Teletext was created in 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 North ...
in the early 1970s by John Adams,
Philips
Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...
' lead designer for video display units. Public teletext information services were introduced by major broadcasters in the UK,
starting with the
BBC #REDIRECT BBC #REDIRECT BBC
Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
's
Ceefax
Ceefax (, punning on "seeing facts") was the world's first teletext information service and a forerunner to the current BBC Red Button service. Ceefax was started by the BBC in 1974 and ended, after 38 years of broadcasting, at 23:32:19 BST ( ...
service in 1974. It offered a range of text-based information, typically including news, weather and TV schedules. Also, paged
subtitle (or
closed captioning
Closed captioning (CC) and subtitling are both processes of displaying text on a television, video screen, or other visual display to provide additional or interpretive information. Both are typically used as a transcription of the audio por ...
) information was transmitted using the same system. Similar systems were subsequently introduced by other television broadcasters in the UK and mainland Europe in the following years. Meanwhile, the UK's
General Post Office introduced the
Prestel
Prestel (abbrev. from press telephone), the brand name for the UK Post Office Telecommunications's Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979. It achieved a maxim ...
system using the same display standards but run over telephone lines using bi-directional
modem
A modulator-demodulator or modem is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by Modulation#Digital modulati ...
s rather than the send-only system used with televisions.
Teletext formed the basis for the
World System Teletext
World System Teletext (WST) is the name of a standard for encoding and displaying teletext information, which is used as the standard for teletext throughout Europe today. It was adopted into the international standard CCIR 653 (now ITU-R BT.653) ...
standard (CCIR Teletext System B), an extended version of the original system.
This standard saw widespread use across Europe starting in the 1980s, with almost all televisions sets including a decoder. Other standards were developed around the world, notably
NABTS
NABTS, the North American Broadcast Teletext Specification, is a protocol used for encoding NAPLPS-encoded teletext pages, as well as other types of digital data, within the vertical blanking interval (VBI) of an analog video signal. It is standar ...
(CCIR Teletext System C) in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
,
Antiope (CCIR Teletext System A) in
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
and
JTES
JTES, the Japanese Teletext Specification, is a protocol used for encoding teletext pages, as well as other types of digital data, within the vertical blanking interval (VBI) of an analog video signal in Japan. It was adopted into the internationa ...
(CCIR Teletext System D) in
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
,
but these were never as popular as their European counterpart and most closed by the early 1990s.
Most European teletext services continued to exist in one form or another until well into the 2000s when the expansion of the
Internet
The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, pub ...
precipitated a closure of some of them. However, many European television stations continue to provide teletext services and even make teletext content available via web and dedicated apps.
The recent availability of
digital television
Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative adva ...
has led to more advanced systems being provided that perform the same task, such as
MHEG-5
MHEG-5, or ISO/IEC 13522-5, is part of a set of international standards relating to the presentation of multimedia information, standardised by the Multimedia and Hypermedia Experts Group (MHEG). It is most commonly used as a language to describ ...
in the UK, and
Multimedia Home Platform
Multimedia Home Platform (DVB-MHP) is an open middleware system standard designed by the DVB project for interactive digital television. The MHP enables the reception and execution of interactive, Java-based applications on a TV-set. Interactive ...
.
History
Teletext is a means of sending text and simple geometric shapes to a properly equipped television screen by use of one of the "
vertical blanking interval
In a raster scan display, the vertical blanking interval (VBI), also known as the vertical interval or VBLANK, is the time between the end of the final visible line of a frame or field and the beginning of the first visible line of the next fra ...
" lines that together form the dark band dividing pictures horizontally on the television screen. Transmitting and displaying subtitles was relatively easy. It requires limited
bandwidth
Bandwidth commonly refers to:
* Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range
* Bandwidth (computing), the rate of data transfer, bit rate or thr ...
; at a rate of perhaps a few words per second. However, it was found that by combining even a slow data rate with a suitable memory, whole pages of information could be sent and stored on the TV for later recall.
In the early 1970s work was in progress in Britain to develop such a system. The goal was to provide UK rural homes with electronic hardware that could download pages of up-to-date news, reports, facts and figures targeting UK agriculture. The original idea was the brainchild of
Philips
Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...
(CAL) Laboratories in 1970.
In 1971, CAL engineer John Adams created a design and proposal for UK broadcasters. His configuration contained all the fundamental elements of classic teletext including pages of 24 rows with 40 characters each, page selection, sub-pages of information and vertical blanking interval data transmission. A major objective for Adams during the concept development stage was to make teletext affordable to the home user. In reality, there was no scope to make an economic teletext system with 1971 technology. However, as the low cost was essential to the project's long-term success, this obstacle had to be overcome.
Meanwhile, the
General Post Office (GPO), whose telecommunications division later became
British Telecom, had been researching a similar concept since the late 1960s, known as
Viewdata
Viewdata is a Videotex implementation. It is a type of information retrieval service in which a subscriber can access a remote database via a common carrier channel, request data and receive requested data on a video display over a separate c ...
. Unlike ''Teledata'', a one-way service carried in the existing TV signal, ''Viewdata'' was a two-way system using telephones. Since the Post Office owned the telephones, this was considered to be an excellent way to drive more customers to use the phones.
In 1972 the BBC demonstrated its system, now known as
Ceefax
Ceefax (, punning on "seeing facts") was the world's first teletext information service and a forerunner to the current BBC Red Button service. Ceefax was started by the BBC in 1974 and ended, after 38 years of broadcasting, at 23:32:19 BST ( ...
("seeing facts", the departmental stationery used the "Cx" logo), on various news shows. The
Independent Television Authority
The Independent Television Authority (ITA) was an agency created by the Television Act 1954 to supervise the creation of "Independent Television" ( ITV), the first commercial television network in the United Kingdom. The ITA existed from 1954 un ...
(ITA) announced its own service in 1973, known as
ORACLE (Optional Reception of Announcements by Coded Line Electronics). Not to be outdone, the GPO immediately announced a 1200/75 baud videotext service under the name
Prestel
Prestel (abbrev. from press telephone), the brand name for the UK Post Office Telecommunications's Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979. It achieved a maxim ...
(this system was based on teletext protocols, but telephone-based).
The TV-broadcast based systems were originally incompatible; Ceefax displayed pages of 24 lines with 32 characters each, while ORACLE offered pages of 22 lines with 40 characters each. In other ways the standards overlapped; for instance, both used 7-bit
ASCII
ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of ...
characters and other basic details. In 1974 all the services agreed on a standard for displaying the information. The display would be a simple grid of text, with some ''graphics characters'' for constructing simple graphics. The standard did not define the delivery system, so both ''Viewdata''-like and ''Teledata''-like services could at least share the TV-side hardware (which at that point in time was quite expensive).
Rollout in the United Kingdom
Teletext launch in Amsterdam, 1980
Following test transmissions in 1973–74, towards the end of 1974 the BBC news department put together an editorial team of nine, including and led by editor Colin McIntyre, to develop a news and information service. Initially limited to 30 pages, the Ceefax service was later expanded to 100 pages and was launched formally in 1976.
It was followed quickly by ORACLE and
Prestel
Prestel (abbrev. from press telephone), the brand name for the UK Post Office Telecommunications's Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979. It achieved a maxim ...
.
Wireless World
''Electronics World'' (''Wireless World'', founded in 1913, and in September 1984 renamed ''Electronics & Wireless World'') is a technical magazine in electronics and RF engineering aimed at professional design engineers. It is produced monthly in ...
magazine ran a series of articles between November 1975 and June 1976 describing the design and construction of a teletext decoder using mainly
TTL
TTL may refer to:
Photography
* Through-the-lens metering, a camera feature
* Zenit TTL, an SLR film camera named for its TTL metering capability
Technology
* Time to live, a computer data lifespan-limiting mechanism
* Transistor–transistor lo ...
devices; however, development was limited until the first TV sets with built-in decoders started appearing in 1977.
The ''"Broadcast Teletext Specification"'' was published in September 1976 jointly by the IBA, the BBC and the British Radio Equipment Manufacturers' Association.
The new standard also made the term "teletext" generic, describing any such system. The standard was internationalised as ''
World System Teletext
World System Teletext (WST) is the name of a standard for encoding and displaying teletext information, which is used as the standard for teletext throughout Europe today. It was adopted into the international standard CCIR 653 (now ITU-R BT.653) ...
'' (WST) by
CCIR.
By 1982 there were two million such sets, and by the mid-1980s they were available as an option for almost every European TV set, typically by means of a plug-in circuit board. It took another decade before the decoders became a standard feature on almost all sets with a screen size above 15 inches (Teletext is still usually only an option for smaller "portable" sets). From the mid-1980s both Ceefax and ORACLE were broadcasting several hundred pages on every channel, slowly changing them throughout the day.
In 1986 WST was formalised as an international standard as CCIR Teletext System B. It was also adopted in many other European countries.
Development in other countries
May 2020 teletext page 100 of German public broadcaster ARD
Besides the US and UK developments, a number of similar teletext services were developed in other countries, some of which attempted to address the limitations of the initial British-developed system, by adding extended character sets or improving graphic abilities. For example, state-owned
RAI
RAI – Radiotelevisione italiana (; commercially styled as Rai since 2000; known until 1954 as Radio Audizioni Italiane) is the national public broadcasting company of Italy, owned by the Ministry of Economy and Finance. RAI operates many ter ...
launched its teletext service, called
Televideo
TeleVideo Corporation was a U.S. company that achieved its peak of success in the early 1980s producing computer terminals. TeleVideo was founded in 1975 by K. Philip Hwang, a Utah State University, Hanyang University graduate born in South Kore ...
, in 1984, with support for
Latin character set.
Mediaset, the main commercial broadcaster, launched its
Mediavideo
''Mediavideo'' was the teletext service broadcast on the primary Mediaset television channels (Rete 4, Canale 5, Italia 1) in Italy.
References
Television in Italy
{{Italy-tv-stub ...
Teletext in 1997. These developments are covered by the different
World System Teletext Levels.
In France, where the
SECAM
SECAM, also written SÉCAM (, ''Séquentiel de couleur à mémoire'', French for ''color sequential with memory''), is an analog color television system that was used in France, some parts of Europe and Africa, and Russia. It was one of th ...
standard is used in television broadcasting, a teletext system was developed in the late 1970s under the name
Antiope. It had a higher data rate and was capable of dynamic page sizes, allowing more sophisticated graphics. It was phased out in favour of
World System Teletext
World System Teletext (WST) is the name of a standard for encoding and displaying teletext information, which is used as the standard for teletext throughout Europe today. It was adopted into the international standard CCIR 653 (now ITU-R BT.653) ...
in 1991.
In North America
NABTS
NABTS, the North American Broadcast Teletext Specification, is a protocol used for encoding NAPLPS-encoded teletext pages, as well as other types of digital data, within the vertical blanking interval (VBI) of an analog video signal. It is standar ...
, the North American Broadcast Teletext Specification, was developed to encoding
NAPLPS
NAPLPS (North American Presentation Level Protocol Syntax) is a graphics language for use originally with videotex and teletext services. NAPLPS was developed from the Telidon system developed in Canada, with a small number of additions from AT&T ...
teletext pages, as well as other types of digital data. NABTS was the standard used for both CBS's
ExtraVision
ExtraVision was a short-lived teletext service created and operated by the American television network CBS in the early to mid-1980s. It was carried in the vertical blanking interval of the video from local affiliate stations of the CBS network. ...
and NBC's very short-lived
NBC Teletext
NBC Teletext was a teletext service provided by the NBC, based on the NABTS standard.
Initial trials started in Los Angeles in 1981. Transmissions started as a regular service on May 16, 1983 after FCC approval, in parallel with CBS similar '' Ex ...
services in the mid-1980s.
Japan developed its own
JTES
JTES, the Japanese Teletext Specification, is a protocol used for encoding teletext pages, as well as other types of digital data, within the vertical blanking interval (VBI) of an analog video signal in Japan. It was adopted into the internationa ...
teletext system with support for Chinese, Katakana and Hiragana characters. Broadcasts started in 1983 by
NHK
, also known as NHK, is a Japanese public broadcaster. NHK, which has always been known by this romanized initialism in Japanese, is a statutory corporation funded by viewers' payments of a television license fee.
NHK operates two terrestr ...
.
In 1986 the four existing teletext systems were adopted into the international standard
CCIR 653 (now
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 sp ...
BT.653) as CCIR Teletext System A (Antiope), B (World System Teletext), C (NABTS) and D (JTES).
Decline
The
World Wide Web
The World Wide Web (WWW), commonly known as the Web, is an information system enabling documents and other web resources to be accessed over the Internet.
Documents and downloadable media are made available to the network through web se ...
began to take over some of the functions of teletext from the late 1990s. However, due to its broadcast nature, Teletext remained a reliable source of information during times of crisis, for example during the
September 11 terrorist attacks
The September 11 attacks, commonly known as 9/11, were four coordinated suicide terrorist attacks carried out by al-Qaeda against the United States on Tuesday, September 11, 2001. That morning, nineteen terrorists hijacked four commerc ...
when webpages of major news sites became inaccessible because of the high demand.
As the web matured, many broadcasters ceased broadcast of Teletext — CNN in 2006 and the BBC in 2012. In the UK the decline of Teletext was hastened by the introduction of
digital television
Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative adva ...
, though an aspect of teletext continues in
closed captioning
Closed captioning (CC) and subtitling are both processes of displaying text on a television, video screen, or other visual display to provide additional or interpretive information. Both are typically used as a transcription of the audio por ...
. In other countries the system is still widely used on standard-definition
DVB
Digital Video Broadcasting (DVB) is a set of international open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium, and are published by a Joint Technical Committee (JTC) o ...
broadcasts.
A number of broadcast authorities have ceased the transmission of teletext services.
* International broadcasters: A live teletext is no longer available on
CNN International
CNN International (CNNI, simply branded on-air as CNN) is an international television channel that is owned by CNN Global. CNN International carries news-related programming worldwide; it cooperates with sister network CNN's national and inte ...
. Although many pages are still available, they have not been updated since 31 October 2006.
*
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 North ...
: the founder of the world's first teletext service, the
BBC #REDIRECT BBC #REDIRECT BBC
Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
, closed its