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JTES, the Japanese Teletext Specification, is a protocol used for encoding
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 ...
pages, as well as other types of digital data, within 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 ...
(VBI) of an analog video signal in Japan. 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 D. It supports the display of Chinese,
Katakana is a Japanese syllabary, one component of the Japanese writing system along with hiragana, kanji and in some cases the Latin script (known as rōmaji). The word ''katakana'' means "fragmentary kana", as the katakana characters are derived fr ...
and
Hiragana is a Japanese syllabary, part of the Japanese writing system, along with ''katakana'' as well as ''kanji''. It is a phonetic lettering system. The word ''hiragana'' literally means "flowing" or "simple" kana ("simple" originally as contrast ...
characters. The service can be used to display subtitles, cyclic text pages or pseudo interactive programs. There's support for presentation of photographs, geometry or sound.


History

The development of teletext in Japan started in 1972, followed by the announcement of the world's first teletext system (
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 ( ...
) by 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. ...
...
in the United Kingdom. Because
Japanese characters The modern Japanese writing system uses a combination of logographic kanji, which are adopted Chinese characters, and syllabic kana. Kana itself consists of a pair of syllabaries: hiragana, used primarily for native or naturalised Japanese wo ...
are different from the
western Western may refer to: Places *Western, Nebraska, a village in the US *Western, New York, a town in the US *Western Creek, Tasmania, a locality in Australia *Western Junction, Tasmania, a locality in Australia *Western world, countries that id ...
alphabets An alphabet is a standardized set of basic written graphemes (called letters) that represent the phonemes of certain spoken languages. Not all writing systems represent language in this way; in a syllabary, each character represents a syllab ...
, Japan proceeded with research and development of a specific transmissions method. Called ''"pattern method"'', it sends scanning signals similar to a
fax Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer o ...
, at a rate 20 times faster than existing methods, but required a
character generator A character generator, often abbreviated as CG, is a device or software that produces static or animated text (such as news crawls and credits rolls) for keying into a video stream. Modern character generators are computer-based, and they can g ...
with a large (at the time) 1-
megabit The megabit is a multiple of the unit bit for digital information. The prefix mega (symbol M) is defined in the International System of Units (SI) as a multiplier of 106 (1 million), and therefore :1 megabit = = = 1000 kilobits. The megabit ...
ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...
. This method was adopted in 1982. The first receiver prototype was capable of displaying 1258 characters, and a 48-
kilobyte The kilobyte is a multiple of the unit byte for digital information. The International System of Units (SI) defines the prefix ''kilo'' as 1000 (103); per this definition, one kilobyte is 1000 bytes.International Standard IEC 80000-13 Quantiti ...
character generation ROM, integrated into a single chip. During the 1970s the problem of
error correction In information theory and coding theory with applications in computer science and telecommunication, error detection and correction (EDAC) or error control are techniques that enable reliable delivery of digital data over unreliable communica ...
(causing wrong characters to be displayed) was studied. These problems were solved in the early 1980s, allowing the service to start. An alternative method of transmission, called ''"hybrid method"'' was developed by NHK in 1979. It allowed faster transmissions rated, and was adopted as a standard in October 1985. Experimental broadcasts started on October 3, 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
Tokyo Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...
and
Osaka is a designated city in the Kansai region of Honshu in Japan. It is the capital of and most populous city in Osaka Prefecture, and the third most populous city in Japan, following Special wards of Tokyo and Yokohama. With a population of 2. ...
using the ''"pattern method"''. This included subtitles and other so called "supplementary" or "independent programs", where information unrelated to the TV program being show is displayed. For example, at the time of the
Great Hanshin Earthquake The , or Kobe earthquake, occurred on January 17, 1995, at 05:46:53 JST (January 16 at 20:46:53 UTC) in the southern part of Hyōgo Prefecture, Japan, including the region known as Hanshin. It measured 6.9 on the moment magnitude scale and had ...
, information about vital services and victim names was broadcast for days. To accompany the introduction of the system,
Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...
released the "TXT-10" decoder with a cost of 119,000
yen The is the official currency of Japan. It is the third-most traded currency in the foreign exchange market, after the United States dollar (US$) and the euro. It is also widely used as a third reserve currency after the US dollar and the e ...
, and
Sharp Sharp or SHARP may refer to: Acronyms * SHARP (helmet ratings) (Safety Helmet Assessment and Rating Programme), a British motorcycle helmet safety rating scheme * Self Help Addiction Recovery Program, a charitable organisation founded in 19 ...
released "21C-L1", a TV with a built in decoder. In 1984
Nippon TV JOAX-DTV (channel 4), branded as , is the flagship station of the Nippon News Network and the Nippon Television Network System, owned-and-operated by the which is a subsidiary of the certified broadcasting holding company , itself a listed su ...
(NTV) experimented teletext between March and July. Regular transmissions started on November 29, 1985 (covering the entire country by 1986) 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 ...
(''"Telemo Japan"'' service) and NTV (''"AXES4"'' service), using the ''"hybrid method"'' In 1986,
TV Asahi JOEX-DTV (channel 5), branded as (also known as EX and and stylized as TV asahi), is a television station that is owned and operated by the subsidiary of certified broadcasting holding company , itself controlled by The Asahi Shimbun Compan ...
started broadcasts with a service named ''"TV Asahi Data Vision"'', that remained active up to 24 July 2011. Other channels, such as
Tokyo Broadcasting System formerly is a Japanese media and licensed broadcasting holding company. It is the parent company of the television network and radio network . It has a 28-affiliate television network called JNN (Japan News Network), as well as a 34-affili ...
( TBS) with ''"Tokyo Data Vision"'' or
TV Tokyo JOTX-DTV (channel 7), branded as and known colloquially as , is a television station headquartered in the Sumitomo Fudosan Roppongi Grand Tower in Roppongi, Minato, Tokyo, Japan, owned and operated by the subsidiary of listed certified b ...
with ''"Nikkei Telepress"'', along with
Fuji TV JOCX-DTV (channel 8), branded as and colloquially known as CX, is a Japanese television station based in Odaiba, Minato, Tokyo, Japan. Owned and operated by the it is the key station of the Fuji News Network (FNN) and the Fuji Network Sys ...
and
Tokyo Metropolitan Television JOMX-DTV, branded as Tokyo MX (officially stylized as TOKYO MX), is an independent television station in Tokyo, Japan, owned by the . It is the only television station that exclusively serves the city. It competes with Nippon TV, TV Asahi, NHK ...
also had teletext services. NHK broadcast 759 hours of teletext per week during 1985, with eight different programs such as news, weather, public announcements and subtitles. As of 1995, 20 television models with built-in teletext receivers were available in the Japanese market.


Description

In a normal
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 ...
video signal there are 525 "lines" of video signal. These are split into two half-images, known as "fields", sent every 60th of a second. These images merge on-screen, and in-eye, to form a single frame of video updated every 30th of a second. Each line of each field takes 63.5 μs to send; 50.3 μs of video and 13.2 μs amount of "dead time" on each end used to signal the television that the line is complete, known as the
horizontal blanking interval Horizontal blanking interval refers to a part of the process of displaying images on a computer monitor or television screen via raster scanning. CRT screens display images by moving beams of electrons very quickly across the screen. Once the be ...
(HBI). When the scanning process reaches the end of the screen it returns to the top during 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 ...
(VBI), which, like the HBI requires some "dead time" to properly frame the signal on the screen. In this case, the dead time is represented by unused lines of the picture signal, normally the top 22 lines of the frame. At the beginning of the service, JTES used four of these lines to transmit information, with 176 bits of data transmitted per scanning line. JTES encodes data into the video signal as a series of dots at a fixed rate of 5.727272 Mbit/s. Each line of a field has 50.3 μs of video area that can be used for transmission, which results in 296 bits per line. It's possible to change the character code set (
JIS C 6226 JIS X 0208 is a 2-byte character set specified as a Japanese Industrial Standard, containing 6879 graphic characters suitable for writing text, place names, personal names, and so forth in the Japanese language. The official title of the current ...
Japanese Industrial Standard, containing 6879 graphic characters suitable for writing text, place names, personal names, etc. in the Japanese language, defined in 1978), in order to express appropriate characters or enhance transmission efficiency. If a character is not available in the teletext receiver character generator, it can be created using ''"DRCS"'' (Dynamically Redefinable Character Sets). Characters can be transmitted as a mosaic of
semigraphic Text-based semigraphics or pseudographics is a primitive method used in early text mode video hardware to emulate raster graphics without having to implement the logic for such a display mode. There are two different ways to accomplish the emu ...
elements, with each element having a resolution of 8 x 12 pixels. There was support for sound generation using the
YM2413 The YM2413, a.k.a. OPLL, is a cost-reduced FM synthesis sound chip manufactured by Yamaha Corporation and based on their YM3812 (OPL2). To make the chip cheaper to manufacture, many of the internal registers were removed. The result of this is th ...
sound chip. Yet sound and images could be transmitted using PCM, using an error correction system called ''"BEST"''. Several information codings are possible: *Mosaic - a mosaic of semigraphic blocks, similar to how graphics are composed on other teletext systems *DRCS - allows characters not available on the character generator *Single layer photographic - transmits image data (pixels, limited number of colors) instead of blocks, significantly slower *Multi layer photographic - transmits images or animations with a large number of colors, much slower *Geometric - generates images from lines, arcs, rectangles and polygons. Similar to
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 standard ...
teletext.


List of Japanese Teletext Services

*'' Telemo Japan'' (
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 ...
) *'' TV Asahi Data Vision'' (
TV Asahi JOEX-DTV (channel 5), branded as (also known as EX and and stylized as TV asahi), is a television station that is owned and operated by the subsidiary of certified broadcasting holding company , itself controlled by The Asahi Shimbun Compan ...
) (7 April 1986 – 24 July 2011) *'' AXES4'' (
Nippon TV JOAX-DTV (channel 4), branded as , is the flagship station of the Nippon News Network and the Nippon Television Network System, owned-and-operated by the which is a subsidiary of the certified broadcasting holding company , itself a listed su ...
) (1985-31 March 2007) *'' Tokyo Data Vision'' ( TBS) *
Fuji TV JOCX-DTV (channel 8), branded as and colloquially known as CX, is a Japanese television station based in Odaiba, Minato, Tokyo, Japan. Owned and operated by the it is the key station of the Fuji News Network (FNN) and the Fuji Network Sys ...
*
Tokyo Metropolitan Television JOMX-DTV, branded as Tokyo MX (officially stylized as TOKYO MX), is an independent television station in Tokyo, Japan, owned by the . It is the only television station that exclusively serves the city. It competes with Nippon TV, TV Asahi, NHK ...
*'' Nikkei Telepress'' (
TV Tokyo JOTX-DTV (channel 7), branded as and known colloquially as , is a television station headquartered in the Sumitomo Fudosan Roppongi Grand Tower in Roppongi, Minato, Tokyo, Japan, owned and operated by the subsidiary of listed certified b ...
)


See also

* Antiope - French teletext standard (CCIR Teletext System A) *
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 standard ...
– North American Broadcast Teletext Specification (CCIR Teletext System C) *
CAPTAIN Captain is a title, an appellative for the commanding officer of a military unit; the supreme leader of a navy ship, merchant ship, aeroplane, spacecraft, or other vessel; or the commander of a port, fire or police department, election precinct, e ...
- Japanese videotex system created by NTT *
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 ...
– North American Presentation Level Protocol Syntax *
Videotex character set The character sets used by Videotex are based, to greater or lesser extents, on ISO/IEC 2022. Three Data Syntax systems are defined by ITU T.101, corresponding to the Videotex systems of different countries. Data Syntax 1 Data Syntax 1 is defin ...
*
Text semigraphics Text-based semigraphics or pseudographics is a primitive method used in early text mode video hardware to emulate raster graphics without having to implement the logic for such a display mode. There are two different ways to accomplish the em ...


References

{{Teletext Television technology Teletext