The Epson HX20

"Your HX-20 is a compact (A4 size), yet powerful battery-operated portable computer designed to meet the computing needs of post-industrial society. The HZ-20's unique mix of the portability of a pocket computer and the functions of a desk top personal computer is made possible by its state-of-the-art miniaturization and consumer-orientated design" A bit of the schpiel from the Epson manual

The HX20 above has a memory expansion unit fitted on the left hand side as well as the optional extra micro data cassette, although the cassette was an optional extra almost all HX20's had one. A rom cartridge could also be fitted in place of the micro cassette.

The inbuilt printer used a 50mm wide till roll and was capable of printing 24 columns of text as well as graphics. The HX20 was described as the first  genuinely portable computer, although there were many before it ,they fell into the luggable category. At only 1.7kg and 290x210 mm this was a truly portable machine, as the machine did not follow a standard design the amount of software was limited. Among the extra's available were software and hardware to communicate via the phone with other machines, including mainframes.

The HX-20 is built round two 6301 processors  a main and slave at a clock speed of 2.45 MHz with a standard ROM of 32k which is expandable up to 64k, the standard amount of RAM was 16k which was expandable to 32k. The display was a liquid crystal display with 4 rows of 20 characters that acts as a window onto a graphic area of  up to 255 x 255, every pixel on the display is addressable therefore giving a graphic resolution of 120 x 32 pixels.

The computer was capable of storing 5 programs in the battery back RAM, this was safe without re-charging for several weeks depending on the amount of use, I have charged one of the unit I have and left it for several months without the warning of low battery appearing.