Teletext Around The World, Still

August 15, 2025 by Al Williams 17 Comments

When you mention Teletext or Videotex, you probably think of the 1970s British system, the well-known system in France, or the short-lived US attempt to launch the service. Before the Internet, there were all kinds of crazy ways to deliver customized information into people’s homes. Old-fashioned? Turns out Teletext is alive and well in many parts of the world, and [text-mode] has the story of both the past and the present with a global perspective.

The whole thing grew out of the desire to send closed caption text. In 1971, Philips developed a way to do that by using the vertical blanking interval that isn’t visible on a TV. Of course, there needed to be a standard, and since standards are such a good thing, the UK developed three different ones.

The TVs of the time weren’t exactly the high-resolution devices we think of these days, so the 1976 level one allowed for regular (but Latin) characters and an alternate set of blocky graphics you could show on an expansive 40×24 palette in glorious color as long as you think seven colors is glorious. Level 1.5 added characters the rest of the world might want, and this so-called “World System Teletext” is still the basis of many systems today. It was better, but still couldn’t handle the 134 characters in Vietnamese.

Meanwhile, the French also wanted in on the action and developed Antiope, which had more capabilities. The United States would, at least partially, adopt this standard as well. In fact, the US fragmented between both systems along with a third system out of Canada until they converged on AT&T’s PLP system, renamed as North American Presentation Layer Syntax or NAPLPS. The post makes the case that NAPLPS was built on both the Canadian and French systems.

That was in 1986, and the Internet was getting ready to turn all of these developments, like $200 million Canadian system, into a roaring dumpster fire. The French even abandoned their homegrown system in favor of the World System Teletext. The post says as of 2024, at least 15 countries still maintain teletext.

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Ceefax: The Original News On Demand

September 30, 2024 by Heidi Ulrich 21 Comments

Long before we had internet newsfeeds or Twitter, Ceefax delivered up-to-the-minute news right to your television screen. Launched by the BBC in 1974, Ceefax was the world’s first teletext service, offering millions of viewers a mix of news, sports, weather, and entertainment on demand. Fast forward 50 years, and the iconic service is being honored with a special exhibition at the Centre for Computing History in Cambridge.

At its peak, Ceefax reached over 22 million users. [Ian Morton-Smith], one of Ceefax’s original journalists, remembers the thrill of breaking stories directly to viewers, bypassing scheduled TV bulletins. The teletext interface, with its limited 80-word entries, taught him to be concise, a skill crucial to news writing even today.

We’ve talked about Ceefax in the past, including in 2022 when we explored a project bringing Ceefax back to life using a Raspberry Pi. Prior to that, we delved into its broader influence on early text-based information systems in a 2021 article.

But Ceefax wasn’t just news—it was a global movement toward interactive media, preceding the internet age. Services like Viditel and the French Minitel carried forward the idea of interactive text and graphics on screen.

Want To Help Capture Some Digital Ephemera? Break Out Your VHS Player

September 26, 2024 by Jenny List 16 Comments

Do you live in the UK, have a VCR and capture card, and an interest in Teletext? [James O’Malley] needs your help! Teletext was, for many people around the world, their first experience of an electronic information system. The simple text and block graphics were transmitted on rotation as data bursts in the frame blanking periods of analogue TV broadcasts, and in an era of printed newspapers, they became compulsory reading. The UK turned off its old-style teletext over a decade ago with the switch to digital, but fragments of the broadcasts remain and can be painstakingly revived from period video recordings with the appropriate software.

This is where [James’] problem begins. Having recovered a very large archive of 1980s and 1990s VHS tapes, he’s come to the realisation that he’s bitten off more than he can chew, and that the archive needs to be in the hands of an individual, entity, or organisation which can give it the resources necessary to archive both the teletext and the programming that it contains. Can you help? Give the article linked above a read.

Meanwhile, you can wallow in a bit of nostalgia by browsing the archive of recovered pages, and while you’re at it, take a minute to envy the French.

Teletext In Ireland, Another Broadcasting Leftover Bites The Dust

October 13, 2023 by Jenny List 14 Comments

Over the years we’ve reported on the passing of a few of the broadcasting technologies of yesteryear, such as analogue TV in America, or AM radio in Europe. Now it’s the turn of an early digital contender, as one of the few remaining holdouts of old-style teletext is to shut down its service. The Irish broadcaster RTÉ is to turn off its teletext service Aertel, which has been live in some form continuously since 1986.

Like all European countries, Ireland has had only digital TV for quite a few years now. The linked RTÉ piece implies that the Aertel service has been carried as the old-style data in the frame blanking period even when part of a digital multiplex rather than the newer digital teletext system, so we’d be really grateful if some of our Irish readers could flick on their TVs and confirm that.

In an internet-connected world it seems quaint that a limited set of curated pages could once have been such a big deal, but it’s easy to forget that for many the teletext system provided their first ever taste of online information. As it shuffles away almost unnoticed we won’t miss counting through the page numbers cycling by in the top corner as we waited for our page to load, but it’s worth marking its final passing from one of the few places it could still be found.

Teletext does pop up in a few projects here, most recently as the display engine for a game of DOOM.

It’s DOOM, But In Teletext

May 20, 2023 by Jenny List 22 Comments

We’ve seen the 1993 id Software classic DOOM running on so many pieces of unexpected hardware, as “Will it run DOOM?” has become something of a test for any new device. But will it run in the circuitry of a 1970s or 1980s TV set? Not quite, but as [lukneu] has demonstrated, it is possible to render the game using the set’s inbuilt Teletext decoder.

Teletext is a technology past its zenith and which is no longer broadcast in many countries, but for those unfamiliar it’s an information service broadcast in the unseen lines hidden in the frame blanking period of an analogue TV transmission. Its serial data packets can contain both pages of text and rudimentary block graphics, and we’re surprised to learn, can include continuous streams to a single page. It’s this feature that he’s used, piping the game’s graphics as a teletext stream which is decoded by the CRT TV and displayed as a playable if blocky game.

Delving further, we find that DOOM is running on a Linux machine on which the teletext stream is created, and the stream is then piped to a Raspberry Pi which does the encoding on to its composite video output. More powerful versions of the Pi can run both processes on the same machine. The result can be seen in the video below, and we can definitely say it would have been mind-blowing, back when DOOM was king. There are plans for further refinement, of which we’d say that color would be the most welcome.

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CEEFAX Lives! (Courtesy Of A Raspberry Pi)

January 7, 2022 by Jenny List 28 Comments

As analogue TV slides from memory, there’s a facet of it that’s fondly remembered by a band of enthusiasts. Teletext was an electronic viewdata information service digitally encoded in the frame blanking period, and a TV set with a decoder chip would provide access to many pages of news and other services all displayed in the characteristic brightly colored block graphics. It went the way of the dinosaur with the demise of analog TV, but for [Nathan Dane] the flame is kept alive with his own private version of the BBC’s CEEFAX service.

He has a particular enthusiasm for analog TV, and as such has his own in-house channel served by a UHF modulator. He shares with us the story of how he arrived at a teletext service, before writing code to scrape the BBC news and weather websites and populate his modern-day CEEFAX. Behind it all is a Raspberry Pi, with a vbit-pi board injecting the teletext signal onto the video, and raspi-teletext creating the pages from source material derived from a set of custom scraper scripts.

We like this project a lot, because while it’s not the first Pi teletext system we’ve encountered, the use of a scraped live feed makes it one of the most creative.

Thanks [kwikius] for the tip!

History Of Closed Captions: The Analog Era

April 14, 2021 by Chris Lott 46 Comments

Closed captioning on television and subtitles on DVD, Blu-ray, and streaming media are taken for granted today. But it wasn’t always so. In fact, it was quite a struggle for captioning to become commonplace. Back in the early 2000s, I unexpectedly found myself involved in a variety of closed captioning projects, both designing hardware and consulting with engineering teams at various consumer electronics manufacturers. I may have been the last engineer working with analog captioning as everyone else moved on to digital.

But before digging in, there is a lot of confusing and imprecise language floating around on this topic. Let’s establish some definitions. I often use the word captioning which encompasses both closed captions and subtitles:

Closed Captions: Transmitted in a non-visible manner as textual data. Usually they can be enabled or disabled by the user. In the NTSC system, it’s often referred to as Line 21, since it was transmitted on video line number 21 in the Vertical Blanking Interval (VBI).

Subtitles: Rendered in a graphical format and overlaid onto the video / film. Usually they cannot be turned off. Also called open or hard captions.

The text contained in captions generally falls into one of three categories. Pure dialogue (nothing more) is often the style of captioning you see in subtitles on a DVD or Blu-ray. Ordinary captioning includes the dialogue, but with the addition of occasional cues for music or a non-visible event (a doorbell ringing, for example). Finally, “Subtitles for the Deaf or Hard-of-hearing” (SDH) is a more verbose style that adds even more descriptive information about the program, including the speaker’s name, off-camera events, etc.

Roughly speaking, closed captions are targeting the deaf and hard of hearing audience. Subtitles are targeting an audience who can hear the program but want to view the dialogue for some reason, like understanding a foreign movie or learning a new language.

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