For the publisher, see Prestel Publishing.Prestel (abbrev. from press telephone), 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 achieved a maximum of 90,000 subscribers in the UK and was eventually sold by BT in 1994.The technology was a forerunner of on-line services today. Instead of a computer, a television set hooked to a dedicated terminal was used to receive information from a remote database via a telephone line. The service offered thousands of pages ranging from consumer information to financial data but with limited graphics.