Prestel
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Prestel, the brand name for the UK Post Office's Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979. It was developed under the leadership of Samuel Fedida at the then Post Office Research Station (now Adastral Park - though insiders still say "the Labs") in Martlesham, Suffolk.
In common with the Ceefax and ORACLE teletext services provided by the BBC and ITV television companies, the system used a modified television to display information in a non-scrolling window of 40x24 text characters, with some simple graphics, conforming to the 1974 CEPT1 standard. Unlike the limited data available on Ceefax and Oracle, Prestel offered an extensive range of information that had been supplied both by a Prestel department at the Post Office and by third-party Information Providers. The range of IPs was wide, including the government and parliament.This data was entered on a central Update Computer, "Duke", located in London, and then mirrored onto a number of satellites (mirrored computers known as IRCs) "Dryden", "Kipling", "Derwent", "Enterprise", "Dickens", "Keats", "Bronte", "Eliot" and "Austen" (among others) that were located throughout the country. Access was open to all users except for a number of CUGs (Closed User Groups) membership of which was provided to a controlled userbase, usually by a paid subscription. Mail was handled by a machine known as "Pandora". They were all GEC 4000 series machines.
Whilst the teletext services were provided free of charge, and were encoded as part of the regular television transmissions, Prestel data was transmitted via telephone lines to a set-top box terminal, and while this enabled interactive services and a crude form of e-mail to be provided, it also involved purchasing a suitable terminal, and paying both a monthly subscription and the cost of local telephone calls. On top of this, some services (notably parts of Micronet800) sold content on a paid-for basis. Each Prestel screen carried a price in pence in the top right-hand corner. Single screens could cost up to 99p.
The original idea was to persuade consumers to buy a modified television set with an inbuilt modem and a keypad remote control in order to access the service, but no more than a handful of models were ever marketed and they were prohibitively expensive. Set-top boxes were pioneered by the Nottingham Building Society for its customers, who could make financial transactions via Prestel.
The access situation improved as home computers became more commonplace, and by the late 1980s it was possible to use a machine such as a BBC Micro or Atari computer, equipped with a 1200/75 baud modem and some simple software, to access the Prestel service. It was possible to buy downloadable content such as simple games. This would be encoded in a series of pages that with body text that was not human-readable but encoded the content in blocks of rather less than 1 kilobyte at a time. The header and footer of these pages was normal, however, so users could watch the pages appearing one after another to build up the downloaded file. To charge for content, the first pages of the downloaded file were charged at 99p each until the total charged was within 99p of the total price, after which one page would be charged at the balance of the total price and subsequent pages were free.
Because the communication over telephone lines did not use any kind of error correction protocol it was prone to interference from line noise which would result in garbled text. This was particularly problematic with early home modems which used acoustic couplers because most home phones were hard-wired to the wall at that time.
However, it was still an expensive proposition, and as a result, Prestel only ever gained a little market penetration among private consumers It did however meet with some limited success among businesses. Consequently the service was moved to British Telecom's commercial division and eventually came to specialise mostly in the provision of financial data.
The 1984 hacker intrusion into the (very likely unused) Prestel mailbox of the Duke of Edinburgh garnered the network some unfavourable press, particularly when the simplicity of its security measures became apparent. The subsequent failure to successfully prosecute the intruders contributed to the introduction of the Computer Misuse Act 1990.
The Prestel name and equipment was eventually sold by British Telecom, and purchased by the Financial Times, in 1994.
Prestel Online, which was an Internet service provider spinoff, was sold to Scottish Telecom, and as of 5 June 2002, has since been merged into their other ISP activities.
The dial-up viewdata service was run down as the Internet gained in popularity, and continues today in name only, as the FT's financial information service.
In contrast to the demise of the British system, the French version of Prestel, Teletel/Minitel, which used the same standard, received substantial public backing when millions of Minitel terminals were handed out free to telephone subscribers. As a consequence the Teletel network became very popular in France, and remains well used, with access now also possible over the Internet.
A closed access Videotex system based on the Prestel model was developed by the travel industry, and continues to be almost universally used by travel agents throughout the country: see Viewdata. The Prestel technology was also sold abroad to several countries, and in 1984 Prestel won a UK Queen's Award for Industry both for its innovative technology and use of British products (it largely ran on equipment provided by GEC).
[edit] References
- Fedida, S. and Malik, R. (1979). The Viewdata Revolution. London, UK, Associated Business Press, ISBN 0-85227-214-6
[edit] See also
- Compunet
- Micronet800
- World War II Colossus computer, also built by the Post Office Research Laboratories.
- UK topics
