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Encyclopedia > Teletext
A BBC Ceefax page from January 9, 2007.
A BBC Ceefax page from January 9, 2007.

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, weather and TV schedules. Subtitle (or closed caption) information is also transmitted in the teletext signal. Image File history File links No higher resolution available. ... January 9 is the 9th day of the year in the Gregorian calendar. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the Anno Domini (common) era. ... Template:A year The 1970s decade refers to the years from 1970 to 1979, inclusive. ...


Teletext information is broadcast in the vertical blanking interval between image frames in a broadcast television signal. It is closely linked to the PAL broadcast system, and most PAL televisions include teletext decoders. Other teletext systems have been developed to work with the SECAM and NTSC systems, but teletext failed to gain widespread acceptance in North America and other areas where NTSC is used. In contrast, teletext is nearly ubiquitous across Europe as well as some other regions, with most major broadcasters providing a teletext service. Common teletext services include TV schedules, regularly updated current affairs and sport news, simple games (such as quizzes) and subtitling for deaf people or in different languages. The vertical blanking interval (VBI) is an interval in a television or VDU signal that temporarily suspends transmission of the signal for the electron gun to move back up to the first line of the television screen to trace the next screen field. ... Television encoding systems by nation PAL, short for Phase Alternating Line, is a colour encoding system used in broadcast television systems in large parts of the world. ... A Digitrax DH163AT DCC decoder in an Athearn locomotive before the shell goes on. ... SECAM, also written SÉCAM (Séquentiel couleur à mémoire, French for sequential color with memory), is an analog color television system first used in France. ... The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ... This article is very long. ...


Teletext uses a numbered page metaphor to present its information, all of which is broadcast in sequence; when a viewer keys in a page number, the receiver waits until that information is broadcast again, typically within a few seconds, and retrieves it for display on-screen. More sophisticated systems use a buffer memory to store some or all of the teletext pages, for instantaneous display. The terms storage (U.K.) or memory (U.S.) refer to the parts of a digital computer that retain physical state (data) for some interval of time, possibly even after electrical power to the computer is turned off. ...


Because of its presentation of user-requested graphic information, Teletext can be seen as a predecessor of the World Wide Web. Unlike the internet, teletext is broadcast, so it does not slow down further as the number of users increase. It has proved to be a reliable text news service during events such as the September 11, 2001 terrorist attacks, during which the webpages of major news sites became inaccessible due to unexpected demand. Teletext is used for carrying special packets interpreted by TVs and video recorders, containing information about channels, programming etc. (see "Other Teletext-related services"). WWWs historical logo designed by Robert Cailliau The World Wide Web (WWW or simply the Web) is a system of interlinked, hypertext documents that runs over the Internet. ... Broadcasting in a computer network refers to transmiting a packet that will be received (conceptionally) by every device on the network. ... The World Trade Center on fire The September 11, 2001 attacks were a series of coordinated terrorist attacks against the United States on September 11, 2001. ...


Although the term "teletext" tends to be used to refer to the PAL-based system, or variants, the recent availability of digital television has led to more advanced systems being provided that perform the same task, such as MHEG-5 in the UK, and Multimedia Home Platform. Digital television (DTV) is a telecommunication system for broadcasting and receiving moving pictures and sound by means of digital signals, in contrast to analog signals used by analog (traditional) TV. DTV uses digital modulation data, which is digitally compressed and requires decoding by a specially designed television set, or a... MHEG-5 is a specification devised for the middleware of digital teletext services in the United Kingdom. ... Multimedia Home Platform (DVB-MHP) is an open middleware system standard designed by the DVB project for interactive digital television. ...

Contents

Development

An experimental BBC Ceefax teletext page from 1975
An experimental BBC Ceefax teletext page from 1975
a "brief specification" from IBA engineering
a "brief specification" from IBA engineering
"This is ORACLE"
"This is ORACLE"

In about 1970 the BBC had a brainstorming session in which it was decided to start researching ways to send closed captioning information to audience. As the Teledata research continued they became increasingly interested in using the same system for delivering any sort of information, not just closed captioning. Displaying subtitles requires limited bandwidth, at a rate of perhaps a few words per second. However, by combining even a slow data rate with a suitable memory, pages of information could be sent and stored in the TV for later recall. Image File history File links No higher resolution available. ... Image File history File links Download high resolution version (1068x566, 117 KB) Summary Oracle data organisation (from This is Oracle, IBA Engineering, Issue 2, EIS/80) Licensing File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Download high resolution version (1068x566, 117 KB) Summary Oracle data organisation (from This is Oracle, IBA Engineering, Issue 2, EIS/80) Licensing File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Download high resolution version (1274x1755, 185 KB) Summary This is Oracle, IBA Engineering Service. ... Image File history File links Download high resolution version (1274x1755, 185 KB) Summary This is Oracle, IBA Engineering Service. ... The British Broadcasting Corporation, usually known as the BBC (and also informally known as the Beeb or Auntie) is the largest broadcasting corporation in the world in terms of audience numbers, employing 26,000 staff in the United Kingdom alone and with a budget of more than GB£4 billion... A commonly-used symbol indicating that a program or movie is closed-captioned. ... This article or section does not cite its references or sources. ...


Meanwhile the General Post Office (whose telecommunications division later became British Telecom) had been researching a similar concept since the late 1960s, known as Viewdata. Unlike Ceefax which was 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. The term General Post Office is or has been used by a number of postal and telecommunications governmental administrations worldwide, including: United Kingdom until 1969, see Post Office UK. After 1981 see Royal Mail for a continuing history of the British Post Office. ... BT Group plc (which trades as just BT, and is commonly known by its former name, British Telecom) is the privatised former British state telecommunications operator. ... In telecommunication, a viewdata is a Videotex implementation, a type of information-retrieval service in which a subscriber can (a) access a remote database via a common carrier channel, (b) request data, and (c) receive requested data on a video display over a separate channel. ...


In 1972 the BBC demonstrated their system, now known as Ceefax ("see facts", the departmental stationery used the curious "Cx" logo), on various news shows. The Independent Television Authority (ITA) announced their own service in 1973, known as ORACLE (Optional Reception of Announcements by Coded Line Electronics). A BBC Ceefax page from 10 September 1999 Ceefax (phonetic for See Facts) is the BBCs teletext information service. ... The Independent Television Authority (ITA) was a body created by the Television Act 1954 to supervise the creation of Independent Television (ITV), the first commercial television network in the United Kingdom. ... 1973 (MCMLXXIII) was a common year starting on Monday. ... ORACLE (Optimal Reception of Announcements by Coded Line Electronics) was a commercial teletext service first broadcast on ITV in 1974 and later on Channel 4 in the United Kingdom finally ending on both channels at the end of December 1992. ...


In 1974 all the services agreed a standard for displaying the information. The display would be a simple 40x24 grid of text, with some graphics characters for constructing simple graphics. This standard was called CEPT1. 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). The standard also introduced a new term that covered all such services, teletext.[citation needed] CEPT1 was a standard set in 1974 by the European Conference of Postal and Telecommunications Administrations (CEPT) for the display of Videotex. ...


The "Broadcast Teletext Specification" was published in September 1976 jointly by the IBA, the BBC and the British Radio Equipment Manufacturers' Association. Not to be outdone the GPO immediately announced a 1200/75 baud videotext service under the name Prestel. Prestel, the brand name for the British General Post Offices Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979. ...


Recent versions of the CEPT1 standard are called World System B (also known as WST, or World System Teletext) and commonly known as European teletext. CEPT1 was a standard set in 1974 by the European Conference of Postal and Telecommunications Administrations (CEPT) for the display of Videotex. ... Wikipedia does not yet have an article with this exact name. ...


In 1980 a similar system called Telidon was developed in Canada. It used a simple graphics language that would allow a more complex circuit in the TV to decode not only characters, but simple graphics as well. To do this the graphic was encoded as a series of instructions (graphics primitives) like "polyline" which was represented as the characters PL followed by a string of digits for the X and Y values of the points on the line. This system was referred to as PDI (Picture Description Instructions). Later improved versions of Telidion were called NAPLPS. NAPLPS (North American Presentation Level Protocol Syntax) is a graphics language for use originally with videotex services. ... NAPLPS (North American Presentation Level Protocol Syntax) is a graphics language for use originally with videotex services. ...


Introduction

Following test transmissions in 197374, 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. Wireless World magazine ran a series of articles between November 1975 and June 1976 describing the design and construction of a Teletext decoder using mainly TTL devices, however development was limited until the first TV sets with built-in decoders started appearing in 1977. By 1982 there were two million such sets, and by the mid-80s 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 over 15" (Teletext is still usually only an option for smaller "portable" sets). From the mid-80s both Ceefax and ORACLE were broadcasting several hundred pages on every channel, slowly changing them throughout the day. 1973 (MCMLXXIII) was a common year starting on Monday. ... 1974 (MCMLXXIV) was a common year starting on Tuesday. ... Prestel, the brand name for the British General Post Offices Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979. ... Wireless World was the preeminent British magazine for radio and electronics enthusiasts. ... TTL is an elite band of men and boys that originate, live or are involved in the tadley bmx scene. ... For the album by Ash, see 1977 (album). ... 1982 (MCMLXXXII) was a common year starting on Friday of the Gregorian calendar. ... The 1980s refers to the years of 1980 to 1989. ... The 1980s refers to the years of 1980 to 1989. ...


Function

In the case of the Ceefax and Oracle systems and their successors in the UK, the teletext signal is transmitted as part of the ordinary analogue TV signal but concealed from view in the VBI (Vertical Blanking Interval) television lines which do not carry picture information. The teletext signal is digitally coded as 45-byte packets and can use lines 6–22 and 318–335. Some teletext services use a great number of lines, others, for reasons of bandwidth and technical issues, use less. The resulting data rate is 7000 bit/s per line. (40 usable 7-bit bytes per line, on each of 25 frames per second.) The vertical blanking interval (VBI) is an interval in a television or VDU signal that temporarily suspends transmission of the signal for the electron gun to move back up to the first line of the television screen to trace the next screen field. ... 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. ...


A teletext page comprises one or more frames, each containing a screen-full of text. The pages are sent out one after the other in a continual loop. When the user requests a particular page the decoder simply waits for it to be sent, and then captures it for display. In order to keep the delays reasonably short, services typically only transmit a few hundred frames in total. Even with this limited number, waits can be up to 30 seconds, although Teletext broadcasters can control the speed and priority with which various pages are broadcast.


Modern television sets, however, usually have a built-in memory, often for a few thousand different pages. This way, the teletext decoder captures every page sent out and stores it in memory, so when a page is requested by the user it can be loaded directly from memory instead of having to wait for the page to be transmitted. When the page is transmitted again, the television checks if the page in memory is still up-to-date and updates it if necessary.


The text can be displayed instead of the television image, or superimposed on it (a mode commonly called mix). Some pages, such as subtitles (closed captioning) are in-vision, meaning that text is displayed in a block on the screen covering part of the television image. A commonly-used symbol indicating that a program or movie is closed-captioned. ...


The original standard provides a monospaced 40×24 character grid. The standard was improved in 1976 to allow for improved appearance and the ability to individually select the color of each character from a palette of 8. The proposed higher resolution Level 2 (1981) was not adopted in Britain (in-vision services from Ceefax & ORACLE did use it at various times however, though even this was ceased by the BBC in 1996), although transmission rates were doubled from two to four lines a frame in 1981. 1976 (MCMLXXVI) was a leap year starting on Thursday. ... 1981 (MCMLXXXI) was a common year starting on Thursday of the Gregorian calendar. ... 1981 (MCMLXXXI) was a common year starting on Thursday of the Gregorian calendar. ...


Other systems

A number of similar teletext services were developed in other countries, some of which attempted to address the limitations of the British-developed system, with its simple graphics and fixed page sizes.


France:Antiope

Main article: Antiope (teletext)

In France, where the SECAM 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 standard teletext in 1991. Antiope was a French teletext standard in the 1980s. ... SECAM, also written SÉCAM (Séquentiel couleur à mémoire, French for sequential color with memory), is an analog color television system first used in France. ...


Canada:Telidon

Main article: Telidon

The CBC ran a teletext service, IRIS, accessible only in Calgary, Toronto and Montreal. It ran from 1983 until about 1986, and used the Canadian-developed Telidon system, which was developed in 1980. Like Antiope, Telidon allowed significantly higher graphic resolution than standard teletext. NAPLPS (North American Presentation Level Protocol Syntax) is a graphics language for use originally with videotex services. ... The Canadian Broadcasting Corporation (CBC), a Canadian crown corporation, is the country’s national public radio and television broadcaster. ... Calgary is a city in the province of Alberta, Canada. ... Template:Hide = Motto: Template:Unhide = Diversity Our Strength Image:Toronto, Ontario Location. ... This article needs cleanup. ... See also: 1982 in Canada, other events of 1983, 1984 in Canada and the Timeline of Canadian history. ... NAPLPS (North American Presentation Level Protocol Syntax) is a graphics language for use originally with videotex services. ...


United States

A version of the European teletext standard designed to work with the NTSC television standard used in North America was first demonstrated in the USA in 1978 by American television network CBS, which decided to try both the British Ceefax and French Antiope software for preliminary tryouts for a teletext service using station KMOX (now KMOV) in St. Louis, Missouri as a testing ground. CBS decided on Antiope, and the service premiered on station KNXT (now KCBS) in Los Angeles. Also in 1978, station KSL in Salt Lake City, Utah, also premiered a teletext service using Ceefax. The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ... World map showing North America A satellite composite image of North America. ... CBS is one of the largest radio and television networks in the United States. ... A BBC Ceefax page from 10 September 1999 Ceefax (phonetic for See Facts) is the BBCs teletext information service. ... Antiope was a French teletext standard in the 1980s. ... KMOV-TV/DT, News4 Saint Louis is the CBS television affiliate in St. ... This article or section does not adequately cite its references or sources. ... KNXT is a television station owned and operated by the Diocese of Fresno, broadcasting on channel 49. ... KCBS is the callsign of the Columbia Broadcasting Systems three flagship broadcast stations in the United States: KCBS-TV (Channel 2) is the CBS television affiliate serving the Los Angeles area. ... Flag Seal Nickname: City of Angels Location Location within Los Angeles County in the state of California Coordinates , Government State County California Los Angeles County Mayor Antonio Villaraigosa (D) Geographical characteristics Area     City 1,290. ... KSL-TV, Channel 5 is the NBC affiliate in Salt Lake City, Utah, broadcasting locally in analog on VHF channel 5 and in digital on UHF channel 38. ... Salt Lake City is the capital and the most populous city of the U.S. state of Utah. ...


Adoption in the United States was hampered due to a lack of a single teletext standard and consumer resistance to the high initial price of teletext decoders.


A significant reason for the demise of American teletext was when Zenith introduced built-in closed captioning decoders in TVs in the early 90s, as mandated by the FCC. It was not practical for Zenith to re-design their TV chassis models that previously had teletext decoder support to have both teletext and closed captioning support. So Zenith decided to drop the teletext features, therefore ending teletext service in the US in the early 1990s, considering Zenith was the only major manufacturer of teletext-equipped sets in America. A commonly-used symbol indicating that a program or movie is closed-captioned. ... The FCCs official seal. ...


Nowadays, teletext or other similar technologies in the USA are practically non-existent, with the only technologies resembling such existing in the country being closed captioning, TV Guide On Screen, and XDS (eXtended Data Services). A commonly-used symbol indicating that a program or movie is closed-captioned. ... XDS (eXtended Data Services), previously known as EDS, is an American standard classfied under EIA standard EIA-766 for the delivery of any auxillary data to be sent with a television program, or NTSC video signal. ...


World System Teletext

Main article: World System Teletext

WST was also used for a short time in the USA, with services provided throughout the late 1970s and early 1980s by several regional American TV networks (such as the University of Wisconsin's Infotext service in the mid-1980s, which was carried on several TV stations across Wisconsin, and Agtext, provided by Kentucky Educational Television and carried on KET's stations, both services providing agriculturally oriented information) and major-market U.S. TV stations (such as Metrotext, which was formerly carried on station KTTV in Los Angeles, and KeyFax, formerly on WFLD in Chicago). World System Teletext (or WST) is the name of the first successful standard for encoding and displaying teletext information, and is used as the standard for teletext throughout Europe today. ... The University of Wisconsin–Madison is a public university located in Madison, Wisconsin. ... Official language(s) None Capital Madison Largest city Milwaukee Area  Ranked 23rd  - Total 65,498 sq mi (169,790 km²)  - Width 260 miles (420 km)  - Length 310 miles (500 km)  - % water 17  - Latitude 42°30N to 47°3N  - Longitude 86°49W to 92°54W Population  Ranked... The Kentucky Educational Television network is Kentuckys statewide public television network. ... KTTV, channel 11, is an owned-and-operated television station of the News Corporation-owned Fox Broadcasting Company, based in Los Angeles, California. ... Flag Seal Nickname: City of Angels Location Location within Los Angeles County in the state of California Coordinates , Government State County California Los Angeles County Mayor Antonio Villaraigosa (D) Geographical characteristics Area     City 1,290. ... WFLD-TV is an owned-and-operated television station of the News Corporation-owned Fox Broadcasting Company, based in Chicago, Illinois. ... Nickname: The Windy City, The Second City, Chi Town, City of the Big Shoulders, The 312, The City that Works Motto: Urbs In Horto (Latin: City in a Garden), I Will Location in Chicagoland and Illinois Coordinates: Country United States State Illinois County Cook & DuPage Incorporated March 4, 1837 Government...


Zenith manufactured models of television sets in the USA in the 1980s, most notably their Digital System 3 line, that had built-in WST teletext decoders as a feature, much like most British/European TV sets. Teletext services in the USA like Electra could be received with one of these sets, but these were mostly more expensive higher-end sets offered by Zenith, possibly causing Electra (and American teletext in general) to never catch on with the public. Zenith Electronics Corporation is a manufacturer of televisions in the USA. It was the inventor of the modern remote control, and it introduced HDTV in North America. ...


Australian company Dick Smith Electronics (DSE) also offered through their USA distributors a set-top WST teletext decoder kit. The kit used as its core the same teletext decoding module (manufactured by UK electronics company Mullard) installed in most British TV sets, with additional circuitry to adapt it for American NTSC video, and to utilize it in a separate set-top box. Dick Smith Electronics is an Australasian electronics retailer founded in 1968 by Dick Smith. ... For other senses of the word code, see code (disambiguation). ... Mullard Limited was a British manufacturer of electronic components. ... The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ...


The successor of WST in Europe and other countries is based on the Enhanced Teletext Specification from ETSI. ETSI EN300706 classifies Teletext in Level 1.5, Level 2.5 and Level 3.5. Level 1.5 covers all European languages plus Arabic and Hebrew. Level 2.5 provides display enhancements. Level 3.5 adds proportional fonts and high resolution graphics. Level 1.5 is the most popular Teletext standard in analogue and DVB transmissions in Europe. Sometimes it is called 'classical' Teletext. Level 3.5 was outperformed through the success of html and other modern standards.


Teletext differs in navigation methods provided by the broadcaster like FLOF (link information for a tree of pages) or TOP (Table of Pages).


NABTS

Main article: NABTS

Later, an official North American standard of teletext, called NABTS (North American Broadcast Teletext Specification) was developed in the early 1980s by Norpak, a Canadian company. NABTS provided improved graphic and text capability over WST, but was quite short-lived. This was mainly due to the expensive cost of NABTS decoders, costing in the thousands of dollars upon their release to the public. NABTS, however, was adopted for a short while by American TV networks NBC & CBS throughout the early-to-mid 80s, CBS using it for their short-lived ExtraVision teletext service, which premiered after the early Antiope & Ceefax trials by CBS, KNXT, and NBC, who had a NABTS-based service for a very short time in the mid-1980s. NBC discontinued their service in 1986 due to the cost of NABTS decoders not dropping to an affordable level for the consumer public. NABTS (North American Broadcast Teletext Specification) is a protocol utilized for the encoding of digital data within the VBI (vertical blanking interval) of an analog video signal. ... NABTS (North American Broadcast Teletext Specification) is a protocol utilized for the encoding of digital data within the VBI (vertical blanking interval) of an analog video signal. ... Norpak is a company headquartered in Kanata, Ontario, Canada, that specializes in the development of systems for television-based data transmission. ... NBC (an acronym for National Broadcasting Company, its former corporate name) is an American television network headquartered in the GE Building in New York Citys Rockefeller Center. ... CBS is one of the largest radio and television networks in the United States. ... ExtraVision was a short-lived teletext service created and operated by the American television network CBS in the early 1980s. ...


The NABTS protocol received a revival of sorts in the late 90s, when it was used for the datacasting features of WebTV for Windows under Windows 98, and for Intel's now-defunct InterCast service (also for Windows as well), using a proper TV tuner card (such as the ATI All-In-Wonder or Hauppauge's Win-TV). Datacasting is the broadcasting of data over a wide area via radio waves. ... This article or section does not cite its references or sources. ... Windows 98 (codenamed Memphis) is a graphical operating system released on June 25, 1998 by Microsoft and the successor to Windows 95. ... Intel Corporation (NASDAQ: INTC, SEHK: 4335), founded in 1968 as Integrated Electronics Corporation, is an American multinational corporation that is best known for designing and manufacturing microprocessors and specialized integrated circuits. ... Intercast was a short-lived technology developed in 1996 by Intel for broadcasting information such as web pages and computer software along with a television channel. ... Hauppauge WinTV TV tuner card A TV tuner card is a computer component that allows television signals to be received by a computer. ... The current version of the article or section is written like a magazine article instead of the formal tone expected of an encyclopedia. ... Hauppauge Computer Works, or just Hauppauge (pronounced ) for short, is a United States manufacturer and marketer of electronic video hardware for personal computers. ...


InterCast was a modern teletext-like system created by Intel in 1996, using a TV tuner card installed in a desktop PC running Windows with the InterCast Viewer software. The software would receive data representing HTML pages via the VBI (Vertical Blanking Interval) of a television channel's video, while displaying in a window in the InterCast software the TV channel itself. The HTML data received would then be displayed in another window in the Intercast software. It usually was extra supplemental information relevant to the TV program being viewed, such as extra clues for the viewer during a murder mystery show, or extra news headlines or extended weather forecasts during a newscast. Intel Corporation (NASDAQ: INTC, SEHK: 4335), founded in 1968 as Integrated Electronics Corporation, is an American multinational corporation that is best known for designing and manufacturing microprocessors and specialized integrated circuits. ... 1996 (MCMXCVI) was a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ... Apple Macintoshes like the iMac Core Duo are personal computers. ... HTML, short for HyperText Markup Language, is the predominant markup language for the creation of web pages. ... The vertical blanking interval (VBI) is an interval in a television or VDU signal that temporarily suspends transmission of the signal for the electron gun to move back up to the first line of the television screen to trace the next screen field. ... HTML, short for HyperText Markup Language, is the predominant markup language for the creation of web pages. ...


NBC, as well as The Weather Channel, CNN and M2 (now MTV2), utilized InterCast technology to complement their programming. InterCast, however, fell into disuse, and Intel discontinued support of InterCast a few years later. NBC (an acronym for National Broadcasting Company, its former corporate name) is an American television network headquartered in the GE Building in New York Citys Rockefeller Center. ... // The Weather Channel in the early days, had to use a projector which would be turned on to display a picture of the weather map on the wall, which showed satellite pictures and radar images with no movement, The Weather Channel still uses some of the old weather maps, their... The Cable News Network, commonly known as CNN, is a major cable television network founded in 1980 by Ted Turner. ... MTV2 is a cable network that is widely available in the United States on digital cable and satellite television, and is progressively being added to basic cable lineups across the nation. ...


Electra

Main article: Electra (teletext)
Electra teletext
Electra teletext

Perhaps the most prominent of American teletext providers was the Electra teletext service, which was broadcast starting in the early 1980s on the vertical blanking interval (VBI) of the American cable channel WTBS. Electra was owned and operated by Taft Broadcasting and Satellite Syndicated Systems (SSS). Electra ran up until 1993, when it was shut down due to Zenith, the prominent (and only) American TV manufacturer at the time offering teletext features in their sets decided to discontinue such features, as well as a lack of funding and lagging interest in teletext by the American consumer. Electra was a teletext service in the United States that was in operation from the early 1980s up until 1993, when it was shut down due to a lack of funding, and discontinuation of teletext-capable television sets by the only US television manufacturer offering teletext capability at the time... Image File history File links Zenith-electra. ... Image File history File links Zenith-electra. ... Electra was a teletext service in the United States that was in operation from the early 1980s up until 1993, when it was shut down due to a lack of funding, and discontinuation of teletext-capable television sets by the only US television manufacturer offering teletext capability at the time... The vertical blanking interval (VBI) is an interval in a television or VDU signal that temporarily suspends transmission of the signal for the electron gun to move back up to the first line of the television screen to trace the next screen field. ... TBS Superstation is a popular American cable TV network that shows sports and variety programming. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Satellite Syndicated Systems was a company based in Tulsa, Oklahoma in the 1980s that provided distribution services of data for American teletext and other data services via communications satellite. ... In broad terms, the zenith is the direction pointing directly above a particular location (perpendicular, orthogonal). ...


WaveTop

Main article: WaveTop

Another service in the USA similar in delivery and content to teletext was the WaveTop service, provided and operated by the Wavephore Corporation. It used the same types of InterCast-compatible TV tuner cards, and used an application that ran under Windows, like InterCast. In fact, WaveTop software was also bundled with TV tuner cards that had InterCast software bundled with them as well.


However, Wavetop was an independent service from InterCast, and wasn't a complementary service to a television program or channel like the latter In fact, viewing television with a TV card was not possible while the WaveTop software was running, since the software utilized the TV tuner card as a full-time data receiver.


WaveTop provided content from several different providers in the form of HTML pages displayed in the WaveTop software, such as news articles from the New York Times, weather information provided by The Weather Channel, and sports from ESPN. It also delivered short video clips, usually commercials, that could be viewed in the software as well. The New York Times is an internationally known daily newspaper published in New York City and distributed in the United States and many other nations worldwide. ... // The Weather Channel in the early days, had to use a projector which would be turned on to display a picture of the weather map on the wall, which showed satellite pictures and radar images with no movement, The Weather Channel still uses some of the old weather maps, their... ESPN (which formerly stood for Entertainment and Sports Programming Network) is an American cable television network dedicated to broadcasting sports-related programming 24 hours a day. ...


When it was in operation, WaveTop's data was delivered on the VBI of local public TV stations affiliated with the PBS network through their PBS National Datacast [1] division, that the TV card & WaveTop software tuned into to receive the service. The vertical blanking interval (VBI) is an interval in a television or VDU signal that temporarily suspends transmission of the signal for the electron gun to move back up to the first line of the television screen to trace the next screen field. ... Not to be confused with Public Broadcasting Services in Malta. ... National Datacast Incorporated (NDI) is the subsidiary of the Public Broadcasting Service which handles datacasting on PBS TV stations throughout the United States. ...


Guide+

Main article: Guide Plus

Yet another service in the U.S. that relied on data delivery via the VBI like teletext, was the Guide+ (Guide Plus, also referred to as GuidePlus+ as well) service provided and developed by Gemstar. There were several models of television sets made throughout the 90s by Thomson Consumer Electronics under the RCA and General Electric brands that had built-in Guide+ decoders. Guide+ was an on-screen interactive program guide that provided current TV schedule listings, as well as other information like news headlines. Some Guide+ equipped sets from RCA even had an IR-emitting sensor that could be plugged in to the back of the TV, to control a VCR to record programs which could be selected from the on-screen Guide+ listings. In some ways, this was very similar to the Video Programming by Teletext (VPT), Video Program System (VPS), and Programme Delivery Control (PDC) features of British/European teletext. The GUIDE Plus+ System is an interactive Electronic Programme Guide system that is used in consumer electronics products, such as DVD recorders, personal video recorders, digital TVs, plasma displays and LCD televisions. ... The vertical blanking interval (VBI) is an interval in a television or VDU signal that temporarily suspends transmission of the signal for the electron gun to move back up to the first line of the television screen to trace the next screen field. ... This article concerns the media and entertainment company. ... RCAs logo as seen today on many products. ... GE redirects here. ... Look up ir in Wiktionary, the free dictionary. ... Programme Delivery Control is a standard (ETS 300 231) to control video recorders using hidden codes in the teletext service. ... This article is about PDC/StarText teletext programme listings. ...


Guide+ was a free service, supported by advertisements displayed on-screen in the Guide+ menu and listing screens, not unlike banner ads displayed on web pages. Guide+ was delivered over the VBI of select local American TV stations. A web banner or banner ad is a form of advertising on the World Wide Web. ... The vertical blanking interval (VBI) is an interval in a television or VDU signal that temporarily suspends transmission of the signal for the electron gun to move back up to the first line of the television screen to trace the next screen field. ...


Guide+ was discontinued by Gemstar in June 2004, and soon afterwards, Thomson dropped the Guide+ features from all RCA and GE television sets made afterward. This article concerns the media and entertainment company. ...


However, Guide+ in America has now been replaced by Gemstar with a similar service (delivered in the same fashion via VBI like Guide+), called TV Guide On Screen [2]. A small amount of televisions, DVD recorders, and digital video recorders are now being released with TV Guide On Screen capabilities. The Guide+ name & service is still used in Europe by Gemstar. (The same service is known in Japan as G-Guide). Guide Plus+ (in Europe), TV Guide On Screen (in Northern America) or G-Guide (in Japan) is an interactive electronic programme guide system that is used in consumer electronics products, such as television sets, DVD recorders, personal video recorders, and other digital television devices. ... DVR with built-in DVD recorder. ... Foxtel IQ, a digital video recorder and a digital cable set-top box. ...


Star Sight

Main article: Star Sight

Similar to Guide+ was Star Sight [3], with its decoders built in to TVs manufactured by Zenith, Samsung, Sony, Toshiba, Magnavox, and others. This was an electronic program guide service similar to Guide+, but was a service that relied on monthly subscription fees paid by the user, not from revenue gathered from on-screen advertisements like Guide+. Star Sight discontinued operations on July 21, 2003, due to a lack of subscribers to the service. Star Sight's data was also delivered on the VBI of local PBS stations through the PBS National Datacast division, much like how WaveTop was delivered as mentioned previously in this article. 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... The vertical blanking interval (VBI) is an interval in a television or VDU signal that temporarily suspends transmission of the signal for the electron gun to move back up to the first line of the television screen to trace the next screen field. ...


Later developments

While the basic teletext format has remained unchanged in more than 30 years, a number of improvements and additions have been made.

  • Various other kinds of information are sent over the Teletext protocol. For instance, Programme Delivery Control signals—used by video recorders for starting/stopping recording at the correct time even during changes in programming—are sent as teletext packets. A similar, but different, standard Video Programming System is also used for this purpose.
  • Teletext pages may contain special packages allowing VCR's to interpret their contents. This is used in relation to the Video Programming by Teletext (also known as startext) system which allows users to program their videos for recording by simply selecting the program on a teletext page with a listing of programs.
  • Other standards define how special teletext packets may contain information about the name of the channel and the program currently being shown.

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. ... An electronic program (or programme) guide, or EPG, is a program schedule, typically broadcast alongside digital television or radio signals. ... NexTView is an Electronic Programme Guide for the analog domain. ... A Hexdump of a JPEG image. ... This article is about PDC/StarText teletext programme listings. ... Programme Delivery Control is a standard (ETS 300 231) to control video recorders using hidden codes in the teletext service. ...

Video Program System

Main article: Video Program System

A closely related service is the Video Program System (VPS), introduced in Germany in 1985. Like teletext, this signal is also broadcast in the vertical blanking interval. It consists only of 32 bits of data, primarily the date and time for which the broadcast of the currently running TV programme was originally scheduled. Video recorders can use this information (instead of a simple timer) in order to automatically record a scheduled programme, even if the broadcast time changes after the user programmes the VCR. VPS also provides a PAUSE code; broadcasters can use it to mark interruptions and pause the recorders, however advertisement-financed broadcasters tend not to use it during their ad breaks. VPS (line 16) definition is now included in the PDC standard from ETSI. Programme Delivery Control is a standard (ETS 300 231) to control video recorders using hidden codes in the teletext service. ... PDC may stand for: Political parties: Parti Démocrate-Chrétien Suisse (Switzerland) Partido Demócrata Cristiano (Chile) Partido Demócrata Cristiano (El Salvador) Personal Digital Cellular, a Japanese mobile phone standard Programme Delivery Control, a standard to control video recorders using codes transmitted in the teletext service. ... The European Telecommunications Standards Institute (ETSI) is a standardization organization of the telecommunications industry (equipment makers and network operators) in Europe, with worldwide projection. ...


Prestel

Main article: Prestel

Prestel was a British information-retrieval system based on Teletext protocols. However, it was essentially a different system, using a modem and the phone system to transmit and receive the data, comparable to systems such as France's Minitel. The modem was asymmetric, with data sent at 75 bit/s, and received 1200 bit/s. This two-way nature allowed pages to be served on request, in contrast to the TV-based systems' sequential rolling method. It also meant that a limited number of extra services were available such as booking event or train tickets and a limited amount of online banking. Prestel, the brand name for the British General Post Offices Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979. ... Prestel, the brand name for the British General Post Offices Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979. ... Minitel 1. ...


Interactive teletext

Some TV channels offer a service called interactive teletext to remedy some of the shortcomings of standard teletext. To use interactive teletext, the user calls a special telephone number with a regular telephone. A computer then instructs the user to go to a certain teletext page which has been assigned to the customer for that session. Usually the page initially contains a menu with options and the user chooses among the options using the buttons on the telephone. When a choice has been made, the selected page is immediately broadcast and can be viewed by the user. This is in contrast with usual teletext where the customer has to wait for the selected page to be broadcast, because the pages are broadcast sequentially. This technology enables teletext to be used for games, chat, access to databases etc. It allows one to overcome the limitations on the number of available pages. On the other hand, only a limited number of users can use the service at the same time, since one page is allocated per user. Some channels solve this by taking into account where the user is geographically calling from and by broadcasting different teletext pages in different geographical regions. In that way, two different users can be assigned the same page number at the same time as long as they don't receive the TV signals from the same source. Another drawback to the technology is the privacy concerns in that many users can see what a user is doing because the interactive pages are received by all viewers. Also, the user usually has to pay for the telephone call to the TV station. For these reasons, these services have largely been superseded by the World Wide Web. The telephone or phone is a telecommunications device which is used to transmit and receive sound (most commonly voice and speech) across distance. ... Look up chat in Wiktionary, the free dictionary. ... WWWs historical logo designed by Robert Cailliau The World Wide Web (WWW or simply the Web) is a system of interlinked, hypertext documents that runs over the Internet. ...


Level 2.5 teletext

Main article: HiText
Comparison between Teletext Level 1.0 and Teletext Level 2.5.
Comparison between Teletext Level 1.0 and Teletext Level 2.5.

A new graphic standard found its way to the European market around 2000: Level 2.5 or HiText. With Level 2.5 it is possible to set a background colour and have higher resolution text and images. However, very few television stations transmit their teletext in this new standard. 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. HiText is a new, high-definition teletext standard which started to appear in Europe around 2000. ... Image File history File links Download high-resolution version (1440x576, 526 KB) Comparison between Teletext Level 1. ... Image File history File links Download high-resolution version (1440x576, 526 KB) Comparison between Teletext Level 1. ... 2000 (MM) was a leap year starting on Saturday of the Gregorian calendar. ...


However, the system has not been widely implemented, with only a handful of European state broadcasters supporting it. Television stations which are known to transmit teletext in Level 2.5 include the Dutch public broadcaster NOS (background colour on all pages, and a test page with hi-res graphics) and the German ZDF and Bayerisches Fernsehen (completely backwards-compatible Level 2.5 teletext, with higher quality text and graphics on nearly all pages), as well as Arte and 3sat on some pages. The Nederlandse Omroep Stichting (NOS, Netherlands Broadcasting Foundation) is one of the Dutch broadcasters in the Dutch public broadcasting system, Publieke Omroep. ... Zweites Deutsches Fernsehen (Second German Television), ZDF, is a public service German television channel based in Mainz. ... Map of the nine regional broadcasting members of Germanys ARD radio/TV network. ... Arte is a Franco-German TV network, which aims to promote quality programming related to the world of arts and culture. ... 3sats logo 3sat is the name of a public, advertising-free, television network in Central Europe. ...


Digital teletext

Digital television introduced "digital teletext" which, despite the previous teletext standard's digital nature, has entirely different standards, such as MHEG-5 and Multimedia Home Platform. However, standard teletext remains very popular. Some digital television platforms such as Sky Digital in the UK and Ireland incorporate separate teletext streams (used by the BBC from 1998 to 2004, and still used by Irish broadcaster RTÉ), which are provided to the television set in the normal analogue TV manner. Such emulation of analogue teletext on digital TV platforms may ensure its continued use for some time (particularly as there are no plans for an immediate transition to digital terrestrial transmission in some countries, such as Ireland). This emulation is only possible due to the DVB-TXT and DVB-VBI sub-standards of DVB, which allow a set-top box or integrated DVB TV to emulate the vertical blanking interval data in which teletext is carried. MHEG-5 is a specification devised for the middleware of digital teletext services in the United Kingdom. ... Multimedia Home Platform (DVB-MHP) is an open middleware system standard designed by the DVB project for interactive digital television. ... Sky Digital is the brand name for British Sky Broadcastings digital satellite television service, transmitted from SES Astra satellites located at 28. ... Radio Telefís Éireann (RTÉ; Irish for Radio and Television of Ireland) is the national publicly-funded broadcaster of Ireland. ... DVB, short for Digital Video Broadcasting, is a suite of internationally accepted, open standards for digital television maintained by the DVB Project, an industry consortium with more than 300 members, and published by a Joint Technical Committee (JTC) of European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC... DVB, short for Digital Video Broadcasting, is a suite of internationally accepted, open standards for digital television maintained by the DVB Project, an industry consortium with more than 300 members, and published by a Joint Technical Committee (JTC) of European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC... Official DVB logo, found on compliant devices DVB, short for Digital Video Broadcasting, is a suite of internationally accepted, open standards for digital television maintained by the DVB Project, an industry consortium with more than 270 members, and published by a Joint Technical Committee (JTC) of European Telecommunications Standards Institute...


Other Teletext-related services

Various other kinds of information are sent over the Teletext protocol. For instance, Programme Delivery Control signals—used by video recorders for starting/stopping recording at the correct time even during changes in programming—are sent as teletext packets. A similar, but different, standard Video Programming System is also used for this purpose. This article is about PDC/StarText teletext programme listings. ... Programme Delivery Control is a standard (ETS 300 231) to control video recorders using hidden codes in the teletext service. ...


Teletext pages may contain special packages allowing VCR's to interpret their contents. This is used in relation to the Video Programming by Teletext (also known as startext) system which allows users to program their videos for recording by simply selecting the program on a teletext page with a listing of programs.


Other standards define how special teletext packets may contain information about the name of the channel and the program currently being shown.


Cessation of service

A number of broadcast authorities have recently found fit to cease the transmission of teletext services, notably:

See also

This is an extremely incomplete list of teletext services available on different television channels around the world: // [edit] Worldwide BBCfax (BBC World) CNN text (CNN) [edit] Australia Austext (Seven Network) [edit] Belgium VRT-Teletekst (VRT) [edit] Croatia HRT Text (Croatian Radiotelevision) Nova Text (Nova TV) RTL Text (RTL Televizija) Z1... Digital Terrestrial Television (DTTV or DTT) is an implementation of digital technology to provide a greater number of channels and/or better quality of picture and sound using aerial broadcasts to a conventional antenna (or aerial) instead of a satellite dish or cable connection. ... An electronic program (or programme) guide, or EPG, is a program schedule, typically broadcast alongside digital television or radio signals. ... Multimedia Home Platform (DVB-MHP) is an open middleware system standard designed by the DVB project for interactive digital television. ... This article is about PDC/StarText teletext programme listings. ... Videotex is a system for sending of pages of text to a user in computer form, typically to be displayed on a television. ... NAPLPS (North American Presentation Level Protocol Syntax) is a graphics language for use originally with videotex services. ... NABTS (North American Broadcast Teletext Specification) is a protocol utilized for the encoding of digital data within the VBI (vertical blanking interval) of an analog video signal. ...

References

    External links

    Teletext content on the Internet

    • Armenian public television (APTV)
    • Austrian public television (ORF)
    • Austrian/German/Swiss public television (3sat)
    • Belgian public television (RTBF)
    • Belgian public television (VRT)
    • British public television (BBC Ceefax, unofficial site)
    • CNN Worldwide (CNN text)
    • Croatian Radiotelevision (HRT)
    • Czech public television (ČT)
    • Danish public television (DR)
    • Danish commercial TV channel (TV 2)
    • Dutch public television (NOS)
    • Dutch commercial television (NET 5 Text)
    • Dutch commercial television (SBS 6 Text)
    • Dutch commercial television (Veronica Text)
    • Finnish public television (YLE)
    • Finnish commercial TV channel (MTV3)
    • Finnish commercial TV channel (Subtv)
    • Finnish commercial TV channel (Nelonen)
    • German public television (ARD)
    • German public television (ZDF)
    • Hungarian public television (M1 and M2)
    • Icelandic public television (RUV)
    • Irish public television (RTÉ)
    • Italian public television (RAI)
    • Lithuanian TV3 (unofficial site, some reception glitches)
    • Lithuanian LTV (unofficial site, some reception glitches)
    • Norwegian public television (NRK)
    • Polish public television (TVP)
    • Polish commercial TV channel (Polsat)
    • Portuguese public television (RTP)
    • Portuguese private television (SIC)
    • Slovenian public television (RTVSlo)
    • Spanish public television (TVE)
    • Swedish public television (SVT)
    • Swedish TV3
    • Swedish TV4
    • Swiss public television (SF, TSR, TSI)
    • IRIB Teletext (Public Television of Iran)
      • More IRIB Teletext
    • A diary of teletext services from 44 countries on the Internet and links to more than 200 online teletext services

      Results from FactBites:
     
    Teletext - Wikipedia, the free encyclopedia (3762 words)
    Teletext was first demonstrated in the USA in 1978 by American television network CBS, which decided to try both the British Ceefax and French Antiope software for preliminary tryouts for a teletext service using station KMOX (now KMOV) in St.
    Teletext services in the USA like Electra could be received with one of these sets, but these were mostly more expensive higher-end sets offered by Zenith, posibly causing Electra (and American teletext in general) to never catch on with the public.
    Television stations which are known to transmit teletext in Level 2.5 include the Dutch public television (background colour on all pages, and a test page with hi-res graphics) and the German ZDF (completely backwards-compatible Level 2.5 teletext, with higher quality text and graphics on nearly all pages).
    Electra (teletext) - encyclopedia article about Electra (teletext). (1174 words)
    Electra was a teletext service in the United States that was in operation from the early 1980s up until 1993, when it was shut down due to a lack of funding, and discontinuation of teletext-capable television sets by the only US television manufacturer offering teletext capability at the time, Zenith.
    Electra used the WST (World System Teletext) protocol, the same protocol used for teletext in the United Kingdom along with the rest of Europe.
    Electra was one of the very few American teletext services in operation.
      More results at FactBites »

     
     

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