VTX 5000: Part 1 - Prism, Prestel and Teletext

This article is the first part of a series documenting the Prism VTX5000 modem for the ZX Spectrum, which sparked the author's interest in data communications and online communities. It covers the background of teletext systems like Ceefax and Oracle, the SAA5050 Teletext Character Generator chip, and the UK's Prestel viewdata service—the world's first public interactive information system delivered over phone lines. The author also mentions creating a web-based Speccy emulator called ZX84 with potential VTX5000 support. This content is related to vintage computing, technology history, and telecommunications.