The IXI was the world's first
digital audio player. It was invented by
Kane Kramer in 1979.
In 1981 Kramer filed for a UK patent. UK patent 2115996 was issued in 1985, and U.S. Patent 4,667,088 was issued in 1987.
In 1988 Kramer's failure to raise the £60,000 required to renew the patent resulted in the patent entering the public domain, but he is still the owner of the designs.
IXI was around the size of a
credit card and had a
LCD
A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but in ...
screen and navigation and volume buttons. Four
prototype
A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototyp ...
models were built and a pre-production model went on sale at the APRS exhibition at
Earls Court in London, in October 1986.
References
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Original investor's report on the IXI from 1979 (PDF) Format
Digital audio players
Portable media players
Portable audio players