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.
1974? i wonder what hardware was used. a state of the art 4004? even graphics chips were not invented yet. I really would love to know.
I remember getting a copy of the teletext spec from the BBC, and it has a whole section in there about how to generate the characters for display on the TV screen, because, as you say, there were no graphics chips yet, so they couldn’t just leave that as an exercise for the reader!
You can come a long way with a set of shift registers, clock/pll circuits, glue logic and a character rom. But don’t expect it to be small or cheap. That something happened in 1974, doesn’t mean it was available to everyone and it certainly wasn’t cheap and easy.
There are plenty of things you can do without a microcontroller. I’ve read somewhere that it’s even possible to blink an LED without one.
But seriously now, I do love to see the logic/circuits involved in the early stages of ceefax and teletext.
Wireless world, June 1976.
https://www.worldradiohistory.com/UK/Wireless-World/70s/Wireless-World-1976-06.pdf
Wireless world, November 1975.
https://www.worldradiohistory.com/UK/Wireless-World/70s/Wireless-World-1975-12.pdf
Sorry the latter is the December issue. Still important, but…
Here’s the November one.
https://www.worldradiohistory.com/UK/Wireless-World/70s/Wireless-World-1975-11-S-OCR.pdf
Here’s a very early series of articles on building a DIY Teletext decoder : https://www.blunham.com/Radar/Teletext/PDFs/WirelessWorldDecoder.pdf
The author is a very well regarded vision engineer – ex-BBC Outside Broadcasts (and a family friend)
What’s equally amazing is how early Ceefax broadcasts were composed. The earliest hardware I know of was a specialised VDU which could generate Teletext images locally and could output the image to a paper tape. Then the paper tape was read into one of the 30 Core Store pages (each 1kB) and transmitted directly.
So, in the earliest days there was no computer used for either editing, storing, nor transmitting (a 6.98MHz signal in the vertical blanking interval). And you might think that that’s insane, but BBC technical funding was very miserly in the 1970s.
Later they acquired an LSI-11 ‘naked-mini’ computer called Esmerelda which supported 6 terminals for editing and I guess then wrote that directly into a Core Store. This forum post is incredible.
https://retrocomputingforum.com/t/this-is-ceefax-1975/1747
https://www.bbceng.info/additions/2016/The%20History%20Of%20Ceefax.pdf
Putting together a low resolution monochrome character display using 74LS chips isn’t difficult – I did it in my late teens for a homebrew z80 system. Color isn’t much harder with a more expensive TV modulator than the one I used -but I only had a black-and-white TV anyway. Basically you divide a dot clock a to provide addresses to a small ram connected to an EPROM (2708!) that generates the corresponding character pattern. Combinational logic on the divider generates the line and frame blanking and sync pulses, resistively added to the modulator input, and a couple of LS244’s multiplex the ram addresses between the counters and the CPU bus. Fun times!
Sounds a lot like Ben Eater’s video card project.
In South Africa this was called Teletext…same thing, just a different name.
UK had Teletext too, one was on the BBC and the other was the commercial upstart Channel 4.
In the UK the technology was called Teletext, the services delivered via that technology were branded CEEFAX by the BBC, and ORACLE by the company that won the rights to provide a service on ITV (and later Channel Four).
In Norway there is a web hosted “emulation” of the Teletext service that was used by NrK (Norwegian Broadcasting Corporation) we called Tekst (Text) TV. It still kinda works, but most of the pages aren’t getting updated anymore. Still a cool thing to visit and have a look at.
https://www.nrk.no/tekst-tv/100/
I think Ceefax has been confused with Prestel here. Ceefax did not have a return channel. So it is not really interactive as no information can be sent back.
Prestel, on the other hand, was really interactive and very similar to the French Minitel or BTX, which was not so successful in Germany.
The absolutely had interactive ceefax/oracle pages which implemented quizzes and games using the coloured shortcut buttons to pick answers, much in the same was a “choose your own adventure” book works.
BBC Micro mode 7!
In Finland we still have Teletext aka Teksti-TV:
https://yle.fi/aihe/tekstitv
Easily the best way to read all important news.
It’s really worth watching this BBC Ceefax video from 1975. It might look weird and quaint, like the opening shot of technological development being done in a 19th century country mansion that looks like, but isn’t, Bletchley Park. In reality it’s very progressive. For a start, the entire piece is presented by the UK’s first female news presenter: Angela Rippon (who is still alive, and was a competitor on the UK TV show Strictly Come Dancing last year).
At 1:25, Angela Rippon explains that Ceefax only went live in September 1974, 10 months before this broadcast. The editorial room appears at 1:52. You can see what a cheap mess it all is. Basic wooden tables, and secretarial chairs; a seemingly random assortment of screens; a weird, blue keyboard; two blokes handling all the content; hardware in a 19″ rack; wires and paper strewn everywhere.
At 2:00, you can see a bunch of paper tapes curled up in the in-tray (bottom, left). There’s an ASR33 on the Left-hand side. At 2:17, the Teleprinters look quite modern, dot-matrix things (note more tapes behind Smith). Smith explains that it’s just a monitor+keyboard linked to a computer. There’s a hand-written ‘help-sheet’ stuck to the front of the keyboard. There’s a CLI interface to start editing. This monitor can’t even show graphics, just 8-bit text.
Many of the keys have coloured dots on them, I guess that’s help for the UI. 3:16, probably pressing cursor keys? Return/Enter seems to be on the bottom-left. Editing is just overtyping bytes on the screen, like the editor on a Commodore C64. Note at 3:49 when it puts a word into colour, he goes to a space, then types something, that will be a colour code, because Teletext uses serial colour bytes (i.e. you can’t make one half of a word red and the other yellow, as the colour character would create a space).
At 4:21, we see the page number updates, that’s exactly what we’d all see through the 1990s, at that rate. At 4:29 the page selection is mechanical!! The top-left toggle says: “TV/Mix/Data”, like the remote we see later. At 4:42, the Ceefax screen actually announces the 100 page upgrade (it was around 1000 pages or more by the 1990s).
Sub-pages: basically whenever it cycles round to the same page number, it’s possible to broadcast new content for that page, which expanded the amount of information indefinitely. At 5:54 you can see on the map, that it’s possible to present some useful graphics (80×72). At 6:44 it describes subtitling, what we call Closed-Captioning now. At 7:16 it switches to a second (different) terminal in the far-right corner, previously hidden by a supporting column. It’s also got a help-sheet stuck to the terminal. He’s obviously not ‘drawing’ the graphics, but typing one of 64 keys to generate each block pattern. 8:40 Angela Ripon admits that Ceefax is still just an add-on box. At 10:05, the remote control is made by Texas Instruments.
Some incidental cultural examples. Angela Rippon is wearing a Tartan skirt, Tartan was incredibly fashionable in the mid 1970s. And of course, she has massive collars on her blouse. Also, note that when she says: “When”, there’s a distinct ‘h’ sound, very posh! At about 1:00, we see the shop “Woolworth’s” in the background, it went bankrupt in 2015. Then you see the TV is in HMV, which went bankrupt in 2013. At 3:01, the first article is about US President Ford & Vietnam + a possible strike in Dover + the charity Age Concern + a trip by Queen Elizabeth II to Japan.
The first screenshot we see is information from the Financial Times, the same Financial Times that’s gone international. 5:51, the weather map gives temperatures in ºC. This means the UK switched from ºF from no later than the mid-1970s, but the BBC used the term “Centigrade” until the mid 1980s. The newsflash at 6:15 is very significant, it’s describing the end of the British rule of Rhodesia becoming Zimbabwe. The TV show from 6:15 to 6:49 is the infant’s TV show “Play School”. At 8:58 we see a Ceefax page showing the logo for another very popular kids TV show: Blue Peter. From 9:10 she does describe quite well many internet features. Also, at 10:25 she describes the Home computer revolution, which would begin about 5 years later!
Hope this comment isn’t too long for Hackaday!
https://youtu.be/ICoj8mxG0ww?si=Ujskdq0QTLy6evcZ
Watching the video again. I worked out that the display unit used to edit a CEEFAX page, from about 2:40, has a serial interface running at 1200 baud (I timed 7.61s to receive the 960 characters of a page).
Also, at 2:00 you can see the computer in the 19″ rack. It’s a Computer Automation LSI-2, which despite having a similar name to the PDP-11 is quite a different architecture. It’s a 16-bit accumulator + index register architecture. The computer’s position is roughly in-line with the window sill: it’s half-black at the top and possibly brushed aluminium for the bottom half. You can see the orange, square, numeric keypad about 4/5 of the way along the lower half. Below it is a fairly high black expanse, which I guess could be an expansion box? Below that is what looks like another, smaller computer.
The user manual for the LSI-2 is here: http://bitsavers.trailing-edge.com/pdf/computerAutomation/lsi/91-20400-00A2_LSI_Series_Computer_Hbk_Oct74.pdf
So, you can use that to check where it is.
Teletext is still active in the Netherlands, there is even an online version https://nos.nl/teletekst
Check out CEEFAX GPT at https://ceefax.org – a simple experiment where ceefax meets the 21st century!