Teletext was developed in the 1970s in Britain as a way of sending information (text and basic colour graphics) in a PAL television signal.
The BBC implemented it as Ceefax (1974 to 2012), and numerous other broadcasters in PAL countries also used it. In Australia it was called Austext (1982 to 2009) and broadcast on Channel 7.
Apart from screens of information, the technology was also used to provide captions for TV programs (in Australia on page 801 on all networks).
In Australia, it ended in part because the original equipment was at end-of-life, no doubt combined with the rise of the Internet for getting that sort of information.
THE AUSTEXT SERVICE WILL CLOSE ON 30 SEPTEMBER 2009.
The Seven Network started providing test Teletext services in 1977, with live services commencing in 1982 in Brisbane and Sydney.
The Austext service today is still provided using the original 1970’s technology. This equipment has now reached the end of its lifespan.
Unfortunately,it is not possible to replace the existing Austext system with new equipment except at significant cost.
The BBC Micro and teletext
When the BBC Micro was introduced in 1981, this included a graphics mode (Mode 7) that natively supported teletext graphics. Given the computer only originally had 16-32 Kb of RAM, this mode using only 1 Kb was handy to have. It was mostly used by text-based programs, though there was the odd action game implemented in it — I remember a rendition of Space Invaders that used Mode 7.
In schools, BBC Micros could be networked together using the Econet system. A Teletext-like system was available that I think was called Eco-fax — we had that at my high school.
Less common, and only used in Britain, was a special Teletext adaptor, this could be used to download computer programs.
Teletext lives!
Teletext on broadcast television might be long gone, but there’s one place the technology is still used: in Australian racing.
Walk into any betting shop (this photo is from a TAB in Melbourne) and you’ll find these familiar text displays, with 8 colours, the capability of flashing and double-height text, and simple graphics, under the brand name “TabCorp Skytext”.
I have no idea how the signal is broadcast, but it’s definitely the same display technology. Nice to know it lives on, over 45 years since it was devised.
- Ironically, this video from 2012 of highlights of 38 years of Ceefax isn’t playable on modern web browsers because it requires Flash
I distinctly recall years ago as a teen, circa 1993, watching “Home & Away” and flicking through random Teletext pages and landing on one (one of the 800s, I think) that looked like it was part of Channel 7 Melbourne’s internal broadcast system, that displayed the length of the current show segment, how much time was remaining until the next ad break, how long the ad break was scheduled for, and you could watch it update as the TV show aired. I thought that was interesting! Far more interesting than the TV show itself 🙂
Oh my gosh I used to love programming the BBCs, they were such a delight!
I have vivid memories of doing formatting in teletext – and that each bit of formatting (colour, flashing, etc) would cause a blank space, as that character on the screen would in essence be a “control code”. Double-height I recall being a little odd – it would actually cause the line of text to be only the top half of the characters but written the size of a normal character. You would then have to print exactly the same text on the next line with the same double-height code to get the bottom half, which meant you could also make the two halves of the text different colours.
My two favourite things about the BBC though were:
1. The completely integrated Econet meant that the computer itself had some pretty nifty network functionality, such as being able to send instructions to another BBC or better yet read/write memory to/from another BBC. So I’d write a program to read the memory dictating which memory mode another BBC was in, set my screen to match, and then read the relevant video memory for that mode and dump into mine – thus enabling you to see what was on their screen. Could also do things like halt another machine – causing a few of us, well, geeks to write battle programs… we’d each go into a lab of BBCs and try and destroy the other lab’s before they wiped out yours. Lots of fun.
2. There was an interface port underneath the BBC that, again, was fully integrated into the language. So wiring up circuits and turning ports on and off was an absolute piece of cake. Remember this was in the 80s so pioneering stuff for that time. In fact I remember the BBC even supported writing assembly language directly into your BASIC program, which came in handy when we tried controlling stepper motors and BASIC was too slow to control the motor with so that part of the program had to be written in assembly.
Anyways I digress, but the BBC was a very awesome computer. That most software was written in BASIC was even better, I remember a German test program we had to use – displayed a word in English and you had to type it in German. I saved a copy to my personal login space and modified it to accept any keystroke as the correct entry… worked a treat until I let a few friends in on it and with a bunch of us getting perfect scores my scam was out of the bag (though to be fair my punishment was to help the computing department during lunchtimes for a week or two, but to me that was no punishment I continued doing so for several years until socialism became more important).
I remember the BBC compact was an even cooler and smaller BBC, but it lacked the interfacing port so wasn’t as versatile…
Why does my TV still have a teletext button?