June 24, 2021

Teletext: 45 years of history of television technology that preceded the web – La Provincia


British chainBBC, the world’s first to introduce theteletext, has announced that it will stop offering the red button service – heir of traditional teletext. The decline of this technology, with 45 years of history (it did not come to Spain until 1988, although it is still used today), sheds light on a technically rudimentary but precursor system of the Web when it comes to allowing information consultation .

In the times of theGlobal networkmany no longer remember it, but the British television network BBC was the first in the world to introduce teletext on September 23, 1974. This day of the year marks the birth of this technology with the celebration of theNational Teletext Dayin the United Kingdom.

At that time, the chain began to use its own protocol calledCeefax. It was not until years later when the current name of ‘teletext’ began to generalize, derived from the alternative service developed by Oracle. Despite its simplicity, the teletext service remained active on the BBC until 2012.

The British chain opted as a successor of Ceefax for the ‘red button’ system, a similar technology that shows the user additional information in text form, especially news from their channelsBBC NewsYBBC Sport, by pressing the red button on the remote. This last remnant, introduced in 1999, will definitely disappear from the BBC in early 2020, the British network announced in September.

How teletext works

Teletext managed to reach great popularity, with 22 million weekly users only on the BBC, according to the network, and it reports free news, especially sports results, as well as other resources such as programming guides and services such as horoscopes and the weather forecast.

Ceefax even had travel advertising, showing listings of cheap last minute airline tickets and vacation deals. This was the origin of a travel agency that is still maintained (Teletext Holidays).

Despite its technical limitations, teletext has an operation similar to that ofworld Wide Web, a protol that would not be invented until 1989 by the British scientistTim Berners-Lee. Just as you have to wait a while until a web page is loaded, teletext makes use of the analog television signal to send an additional text signal over the spectrum.

The system was developed by BBC engineers two years before its implementation, and takes advantage of the excess capacity of television broadcasts, which at that time was 625 lines.

Ceefax, like its equivalent developed byOracleIndependent Television – later renamed Teletext – benefited from the fact that, due to the cathode ray TV’s hardware, it was necessary to pause about two milliseconds between each frame of the image.

This is explained by the professor of technology at the University of Portsmouth (United Kingdom) Andy Holyer inThe Conversation,which records that Ceefax originally sent the 200 pages that then made up the teletext in order, so the user had to wait until the selected one arrived. Current digital television systems eliminate this wait.

Teletext is shown by default above the television broadcast, originally with text on a black background, but only text with the background channel image can also be displayed. In this way, teletext led to the first accessibility functions such as subtitles and transcriptions, normally located in thepage 888.

Teletext resists in Spain

In Spain, teletext first came through public television (TVE) in 1988, and later with his arrival in private chains asAntenna 3YTelecinco, which began its broadcasts in 1990. Unlike the case of the United Kingdom and the BBC, in Spain this service is maintained in the main channels.

The original model established by TVE and followed by the rest of Spanish channels begins with page 100, which is the cover, with the content index, and then divided into sections (news, sports, services, accessibility …), which normally cover up to page 899.

Technically, Spain’s teletext model is a variant of the first model developed by Oracle, which in 1981 began adding support for new languages ​​in addition to English. This 1.5 implementation has a basic alfamosaic design of40 columns and 24 rows.

The Spanish teletext model stands out especially for the use of a limited color palette: red, green, yellow, blue, pink-magenta, cyan blue and white. Some colors even came to adopt certain meanings, andPink used to be used for adult or erotic content.

The latest study on this technology shows that currently 99.3 percent of Spanish households still have teletext and that 2.3 million people consult this service daily.

Thebroad content themeand commercial uses are some of the examples of applications of teletext, a technology little remembered but that, resisting even after more than 45 years of history, was an antecedent that, in Holyer’s words, “helped us prepare for the world of social networks”.

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