World System Teletext on:
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and services from ''Teletext'' on ITV in the
World System Teletext (WST) is the name of a standard for encoding and displaying
and the UK teletext
A British 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 equipp ...
information, which is used as the standard for teletext throughout Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
today. It was 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) of 1986 as CCIR Teletext System B.
Development
WST originally stems from the UK standard developed by theBBC #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. ...
...Independent Broadcasting Authority
The Independent Broadcasting Authority (IBA) was the regulatory body in the United Kingdom for commercial television ( ITV and Channel 4 and limited satellite television regulation – cable television was the responsibility of the Cable Author ...
in 1974 for teletext transmission, extended in 1976 as the Broadcast Teletext Specification. With some tweaks to allow for alternative national character sets, and adaptations to the NTSC
The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...
525-line system as necessary, this was then promoted internationally as "World System Teletext". It was accepted by CCIR in 1986 under 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 one of four recognised standards for teletext worldwide (most commonly referred to as CCIR Teletext System B).
WST in Europe
Almost all television sets sold in Europe since the early '80s have built-in WST-standard teletext decoders as a feature. WST is used for all teletext services in Europe & Scandinavia, including ''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 ( ...
'' from 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. ...
...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 European mainland, continental mainland. It comprises England, Scotlan ...
, ''ZDFtext'' from ZDF and ''ARDText'' from ARD in Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
, and ''Tekst-TV'' from NRK
NRK, an abbreviation of the Norwegian ''Norsk Rikskringkasting AS'', generally expressed in English as the Norwegian Broadcasting Corporation, is the Norwegian government-owned radio and television public broadcasting company, and the largest ...
in Norway
Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and the ...
, among many other teletext services offered by other television networks throughout the European continent.
WST in the United States
WST saw some use in theUnited 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 territori ...
in the 1980s, for the ''Electra'' service, which was carried on SuperStation WTBS (now TBS). It was also used for other teletext services on other television stations and networks in the US.
Zenith
The zenith (, ) is an imaginary point directly "above" a particular location, on the celestial sphere. "Above" means in the vertical direction ( plumb line) opposite to the gravity direction at that location ( nadir). The zenith is the "high ...
in the US also included built-in WST teletext decoders in their higher-end models of TV sets, such as their line throughout the 1980s. Also, Dick Smith Electronics offered through their American distributors a WST teletext decoder in the form of a set-top box, which was sold as a kit.
This was all in competition to another teletext standard developed exclusively in North America, NABTS (North American Broadcast Teletext Standard). It was developed in Canada by Norpak
Norpak Corporation was a company headquartered in Kanata, Ontario, Canada, that specialized in the development of systems for television-based data transmission. In 2010, it was acquired by Ross Video Ltd. of Iroquois and Ottawa, Ontario.
Norpa ...
, and was used by CBS
CBS Broadcasting Inc., commonly shortened to CBS, the abbreviation of its former legal name Columbia Broadcasting System, is an American commercial broadcast television and radio network serving as the flagship property of the CBS Entertainm ...
for their '' ExtraVision'' service and for a very short time by NBC
The National Broadcasting Company (NBC) is an American English-language commercial broadcast television and radio network. The flagship property of the NBC Entertainment division of NBCUniversal, a division of Comcast, its headquarters are l ...
for their ''NBC Teletext'' in the mid-1980s. However, NABTS never became as successful as WST in the American continent, since NABTS was a more advanced technology, which required a much more complicated and expensive decoder (even though it had improved graphics capability over WST).
Levels
In the early 1980s a number of higher extension levels were envisaged for the specification, based on ideas then being promoted for worldwidevideotex
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 ...
standards (telephone dial-up services offering a similar mix of text and graphics). The proposed higher content levels included geometrically-specified graphics (Level 4), and higher-resolution photographic-type images (Level 5), to be conveyed using the same underlying mechanism at the transport layer. No TV sets currently implement the two most sophisticated levels.
Level 1 (1976)
The initial Broadcast Teletext Specification set out by the BBC, IBA, BREMA in September 1976: * ''Alpha-mosaic characters'' (drawn using a 2×3 block matrix) characters (similar to some characters of the TRS-80 character set) * spacing attributes * fixed colour palette (red, green, yellow, blue, magenta, cyan, white over a black background) * support for double height or flash effect * 40 columns × 24 rows character gridLevel 1.5 (1981)
An extended version of level 1, with support for 13 extended character sets
Character encoding is the process of assigning numbers to graphical characters, especially the written characters of human language, allowing them to be stored, transmitted, and transformed using digital computers. The numerical values that ...
and other 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 ...
-like characters.
*Czech and Slovak
*English
*Estonian
*French
*German
*Italian
*Latvian and Lithuanian
*Polish
*Portuguese and Spanish
*Romanian
*Serbian, Croatian and Slovenian
*Danish, Swedish and Finnish
*Turkish
This is the most common system and still used by most TV channels as of 2021.
Level 2 (1988)
World System Teletext Level 2 was introduced in 1988. New features were: * Multi-language support * 32 colour mode. * Non-spacing attributes * Allows re-definable characters (Level 2 was replaced by level 2.5)Level 2.5 teletext / Hi-Text (1995)
Level 2.5 or ''HiText''. was first broadcast in 1994 by the bilingual French-German channel ARTE
Arte (; (), sometimes stylized in lowercase or uppercase in its logo) is a European public service channel dedicated to culture.
It is made up of three separate companies: the Strasbourg-based European Economic Interest Grouping ARTE, plu ...
. With Level 2.5 it is possible to set a background colour and have higher resolution text and images. The system was adopted initially by ARTE, ARD, ZDF, Bayern 3 and SwissTXT.
New features of Level 2.5 teletext:
* Multi-language support
* Wider colour palette with re-definable colours (4,016 colour palette)
* Non-spacing attributes
* Allows re-definable characters
* Provides side panels for additional text or graphics in 16:9 TVs
* nexTView EPG
Electronic programming guides (EPGs) and interactive programming guides (IPGs) are menu-based systems that provide users of television, radio and other media applications with continuously updated menus that display scheduling information for ...
The system has not been widely implemented, with only a handful of European state broadcasters supporting it.
Television stations which are known to transmit Level 2.5 teletext in the late 2010s include:
* Netherlands: public broadcaster NOS (background colour on all pages, and a test page with hi-res graphics),
* France: France 3
France 3 () is a French free-to-air public television channel and part of the France Télévisions group, which also includes France 2, France 4, France 5 and France Info.
It is made up of a network of regional television services provi ...
* Germany:
** ZDF (some pages),
** 3sat
In logic and computer science, the Boolean satisfiability problem (sometimes called propositional satisfiability problem and abbreviated SATISFIABILITY, SAT or B-SAT) is the problem of determining if there exists an interpretation that satisfies ...
(some pages)
** Bayerisches Fernsehen
Bayerischer Rundfunk (BR; "Bavarian Broadcasting") is a public-service radio and television broadcaster, based in Munich, capital city of the Free State of Bavaria in Germany. BR is a member organization of the ARD consortium of public broadcas ...
(and formerly also now-renamed BR-alpha
ARD alpha is a German free-to-air television channel run by regional public-service broadcaster Bayerischer Rundfunk. Its programming consists of shows made by Bayerischer Rundfunk, as well as from ARD and Austrian broadcaster ORF. The channel ...
) (in the past on almost all pages, now only on some pages),
** phoenix
Phoenix most often refers to:
* Phoenix (mythology), a legendary bird from ancient Greek folklore
* Phoenix, Arizona, a city in the United States
Phoenix may also refer to:
Mythology
Greek mythological figures
* Phoenix (son of Amyntor), a ...
(on some pages),
** Bürgerfernsehen Gera (background-colour on all pages, test pages 460 to 485) and
** SWR Fernsehen (included completely backwards-compatible Level 2.5 teletext, with higher quality text and graphics on nearly all pages).
By late 2021, SWR Fernsehen stopped using the system, but ZDF, 3sat, Bayerisches Fernsehen and Phoenix has at least some Level 2.5 enhanced pages.
One of the problems with Level 2.5 is that it often takes several transmission cycles before the higher resolution items show on the screen. In order to watch Level 2.5 teletext, a rather recent television set with a special decoder chip is required. If not, Level 1.5 text will be shown.
Level 3
New features: * Dynamically Redefined Character Set (DRCS) allowing the display of non- Roman characters (e.g. Arabic and Chinese) * Pictorial graphic characters can also be defined (Level 3 was replaced by level 3.5)Level 3.5 (1997)
Extends the number of re-definable characters and their complexity and introduces different font styles andproportional spacing
A typeface (or font family) is the design of lettering that can include variations in size, weight (e.g. bold), slope (e.g. italic), width (e.g. condensed), and so on. Each of these variations of the typeface is a font.
There are thousands o ...
.
New features:
* Dynamically Redefined Character Set (DRCS) allowing the display of non-Roman characters (e.g. Arabic and Chinese)
* Pictorial graphic characters can also be defined
* Different font styles
* Proportional spacing.
Level 4 (1981)
Level 4 was proposed in 1981 and tested by IBA. No TV set implements this level. *Vector graphics
Vector graphics is a form of computer graphics in which visual images are created directly from geometric shapes defined on a Cartesian plane, such as points, lines, curves and polygons. The associated mechanisms may include vector display ...
in resolutions of 320×256
* Needs computing power to generate the display from a sequence of drawing instructions
* 250,000 colours palette
Level 5
Level 5 allows full-definition still pictures with better quality than video cameras. No TV set implements this level. *Modulated
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...
onto a carrier
* No noise added to the picture during transmission
* Image compression used
See also
* Antiope - French teletext standard (CCIR Teletext System A) * NABTS – North American Teletext Specification (CCIR Teletext System C) * JTES - Japanese Teletext Specification (CCIR Teletext System D) * NAPLPS – North American Presentation Level Protocol Syntax * Mullard SAA5050 a popular teletext decoder chip *List of teletext services
Teletext (or "broadcast teletext") is a television information retrieval service developed in the United Kingdom in the early 1970s. It offers a range of text-based information, typically including national, international and sporting news, weathe ...
* Teletext character set
This article covers technical details of the character encoding system defined by ETS 300 706, a standard for World System Teletext, and used for the Viewdata and Teletext variants of Videotex in Europe.
Character sets
The following tables s ...
* Text semigraphics
Further reading
* ''World System Teletext Technical Specification'', UK Department of Trade and Industry, 1985. Also retitled as ''World System Teletext and Data Broadcasting System Technical Specification'', various revisions until 1989. * CCIR 653 (nowITU-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) set of four standards for teletext systems worldwide. Adopted 1986. Revisions 2 and 3 were published in 1993 and 1998. WST was formalised by this standard as CCIR Teletext System B. Enhanced Teletext specification ETS 300 706 (ETSI, 1997)
Current European standard for CCIR Teletext System B.
References
{{Teletext Teletext