Analogue TV wasn’t the only casualty of the digital switch-over and with London’s switch-off last night, another old friend bit the dust too – Ceefax. The BBC’s teletext service, which was born way back in 1974, brought text news and stories to the decidedly non-digital world, miles before the internet we know and love today was opened-up to the public. Ceefax was your Grandad’s internet.
But if it wasn’t digital and it wasn’t powered by the internet, how did text on your TV actually work? Well the BBC and Teletext ingeniously managed to squeeze their signals into a gap in the analogue broadcast.
The way it worked was thus: in the days of the old CRTs (remember those hulking great big tube televisions?), the magnets used to direct the electron beam couldn’t move instantly. As they scanned across the screen in lines, 576 of them vertically stacked, the magnets needed time to shift their aim at the end of each line down to the start of the next one. That meant that the broadcast had to have a small pause at the end of each line called a Horizontal Blanking Interval, and one at the end of each set of 576 lines to allow the magnets to aim back at the top left corner called the Vertical Blanking Interval. Ceefax was broadcast in those small breaks, spinning line after line of text onto your TV over the air.
Ceefax provided the instant, on-demand news text service that we now take for granted, but before the internet really kicked off. In fact, at one stage Teletext was the holiday-bookers platform of choice; if you ever went on a package holiday as a kid, there was a fair chance your parents booked it on Teletext.
Of course with the rise of digital TV, we got a digital equivalent, widely known as the “red button” services. Digital text is superior in both text quality and can support images and other new-fangled things, but by the time it arrived the internet was in full swing. Whereas Ceefax was the go-to source for up to date and even breaking text news, the digital text services, which are broadcast on their own fancy separate channel, have never really lived up to the legacy.
While I haven’t really used Ceefax since the birth of broadband, I have a myriad of happy childhood memories of sitting in front of the TV while my old man browsed the news with the remote of power. Like analogue TV it’s making way for 4G, so its sacrifice won’t be in vein – it’ll birth something even better for accessing news in the same instant spirit in which it was born. So, it’s with a sad heart I bid Ceefax farewell; it’s the end of an era.
Image credit: vagueonthehow from flickr