© Mark Ollig
The Epson HX-20, a lightweight and portable computer introduced at the 1981 COMDEX (Computer Dealer’s Exhibition) show in Las Vegas, attracted much attention.
The notebook-sized, 3.5-pound lightweight computer was hailed as the first true portable laptop computer.
Another reason for using the Epson HX-20 computer was that it did not require AC power.
This computer came with four rechargeable nickel-cadmium batteries, which could power it for an average of 40 to 50 hours once fully charged after eight hours, allowing people to use the computer from anywhere.
In addition to the quality full-sized keyboard, the Epson HX-20 was the first notebook computer to incorporate a liquid crystal display (LCD) screen; note the Radio Shack TRS-80 Model 100, with an LCD screen, came out in 1983.
The LCD showed four lines of 20 characters in a five-by-seven dot font or 120-by-32 dot graphics. It allowed sideways scrolling to view lines up to 255 characters long.
A removable cartridge housing on the top right above the LCD screen provides access for adding an optional microcassette drive for data storage.
You can load or save data from an audio cassette tape to the HX-20 computer through a serial interface cable with a cassette recorder.
The Epson HX-20 buttons, labeled P1 to P5, are programmable function keys that could control a connected tape recorder or be programmed for other commands.
A 5.25-inch floppy disk could also be used with the HX-20 computer through a serial cable connection to a separate Epson TF-20 external floppy disk drive peripheral device.
The TF-20 weighed 13.2 pounds and contained two floppy drives and a power supply.
The top left corner of the HX-20 holds a built-in 24-column dot-matrix impact paper micro-printer.
The Epson HX-20 includes 32 KB (kilobyte) of internal read-only memory (ROM) using four EPSON BASIC1R0 M66021AA chips, with an expansion socket available to add another eight kilobytes for 40 KB.
Included is 16 KB of random access memory (RAM), expandable to 32 KB, by sliding an expansion module cartridge into a recessed side compartment on the computer case.
The HX-20 is equipped with EPSON BASIC, a command interpreter or compiler that enables it to run BASIC computing code.
BASIC, or Beginner’s All-purpose Symbolic Instruction Code, is a programming language developed at Dartmouth College in Hanover, NH, in 1964. It has been modified over the years for compatibility with later computer models.
The Epson HX-20 computer used two eight-bit C63010CA A16-2H1 microprocessors in a primary/secondary configuration, each with a clocking speed of 614Khz.
The primary CPU managed the operating system, or command interpreter, whereas the secondary CPU handled the display output and keyboard input data. In 1982, this configuration allowed the computer to achieve a relatively high level of performance.
The Nov. 25, 1982, Minneapolis Star and Tribune ran an ad for “the new powerful, affordable, and portable Epson HX-20 for under $800.”
The price was $795, equivalent to $2,475 today.
The Epson HX-20 included software programs such as:
• SkiWriter, a word processor.
• EPSON BASIC, a version of the BASIC programming language designed for the HX-20.
• MailList, to create and manage their mailing lists.
• The Card Index, to store and organize information.
• The Personal Journal, a diary to track thoughts and experiences.
Games, educational, and business software programs were purchased separately.
An HX-20 computer user could access online dial-up computer services using the Epson CX-20 modem attached to a telephone line.
The CX-20 data rate was 300 baud/bits per second; slow, by today’s standards, but fast enough for the text-based online services available in 1982.
Online dial-up commercial computer services included CompuServe, which provided real-time chat, information, email, and news.
In my previous columns, I wrote about the dial-up Bulletin Board Systems (BBS) created and maintained by computer hobbyists. These virtual communities were free for users to join and participate in.
But I digress.
Using the HX-20 RS-232C serial port, the computer could directly connect to an external printer, television monitor, or another computer.
RS-232 is a recommended standard (RS) published by the EIA (Electronic Industries Alliance). The standard number is 232; the ‘C’ version was released in 1969.
In 1980, Yukio Yokozawa invented the Epson HX-20 (the HC-20 in Japan). It was patented and sold by Suwa Seikosha, a branch of Seiko (now Seiko Epson).
The Osborne 1 computer, produced in 1981, has been noted for its portability compared to the Epson HX-20.
First, it was large and heavy, weighing around 25 pounds; others (and I) found it much too cumbersome to be called a lightweight “portable” computer.
Furthermore, unlike the Epson HX-20, which uses internal batteries allowing it to operate from anywhere, the Osborne 1 needed to be plugged into an AC outlet.
Recently, I took my 41-year-old Epson HX-20 computer out of mothball storage.
Even though the computer is old, its well-organized appearance and modern design still hold up.
The Epson HX-20 was the first truly portable laptop personal computer, paving the way for the ones used today.
