Epson HX-20
Announced:November 1981
Available:Late 1982
Weight:3.5 lb / 1.6kg
CPU:Two Hitachi 6301 @ 0.614MHz
RAM:16K, 32K max
Display:20 X 4 text, 120 x 32 graphics
 built-in dot matrix printer
Storageoptional built-in tape drive
optional external disk drive
Ports:RS-232, serial

Introduced at the 1981 COMDEX computer show in Las Vegas, the Epson HX-20 drew great attention as the beginning of a new trend - powerful, battery-operated, briefcase-sized computers. Everything is included for a convenient and useful portable computer - a full-size keyboard, an LCD screen, built-in data storage, and rechargeable batteries.

Only two programs are included with the HX-20 - a built-in Monitor application for direct manipulation of the system memory, and like practically every other personal computer of the 80's, the Microsoft BASIC programming language is also permanently stored in ROM. Press <CTRL>@ to set the date and time, which will be remembered by the battery-backed clock.

Storage device? Yes, there is an optional on-board miniature micro-cassette recorder ($135) for data storage. It is very reliable and easy to use - the data is actually stored twice, and there are no buttons to press - it is controlled entirely by the computer. One micro-cassette tape (30 minute) holds about 50K of data.
The system shown here doesn't have a data recorder installed - there's a 'dummy' module instead.
An optional external cassette recorder can be used, as well as the optional TF-20 floppy disk drive.

The built-in printer is a dot-matrix, impact micro-printer, able to print 24 characters per line, at 42 lines per minute.

The built-in rechargeable batteries provide an amazing battery life of about 50 hours before the system needs to be plugged-in and recharged, but don't forget to turn your HX-20 off when finished using it - it will not automatically power-down after sitting inactive like most battery devices do.

Althought the screen seems rather small - only 4 lines of text, 20 characters per lines - this was one of the largest LCD screens available at the time.

The system bus on the left side of the HX-20 allows the addition of expansion modules, including additional RAM memory, analog I/O, etc. Seen below is the HX-20 with an expansion module, as well as the plastic Epson carrying case.

Related Links

  • Epson support
  • An HX-20 Enthusiast's Site
  • HX-20 from Oh no, not another computer museum!
  • Epson HX-20 computer from
  • Epson HX-20 Consumable Products & Manuals from Star Technology
  • Epson HX-20 from GanjaTron
  • Starring the Computer

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