Epson hx-20

The Epson HX-20 (also known as the HC-20 ) is a laptop computer , often called the first handheld computer (held in the hand). It was announced in November 1981 , but went on sale in 1983. BusinessWeek magazine called it the "fourth revolution in personal computers."

Epson hx-20
Type of	portable computer
Manufacturer
Date of issue	1983
CPU	Two Hitachi 6301 processors at 614 kHz
RAM	16 KB RAM (up to 32 KB) 32 KB ROM (up to 64 KB)
Weight

About the size of an A4 sheet, the Epson HX-20 had a full keyboard , a built-in monochrome LCD display with a resolution of 120 × 32 pixels (smaller than any modern mobile phone), a matrix calculator printer , nickel-cadmium batteries , the EPSON Basic programming language, expandable RAM and removable tape recorder with fail-safe recording. The operating system was Epson's own, which contained an EPSON BASIC language interpreter and a system monitor . The computer allowed you to keep up to 5 running programs and files in RAM, instantly switch between them and exchange data. The main bus of the computer was serial, all external interfaces, including the output of an external monitor, were serial. The cassette in the tape recorder was formatted before use, which greatly simplified the handling of the computer: the user did not need to rewind the tape to the desired location on his own - the information was searched automatically.

Weight is approximately 1.6 kg . Popular body colors are silver and cream , although some prototypes were dark gray. The HX-20 came with a gray case. Also available:

• external modem CX-20,
• external TF-20 drive (the interface is compatible with Commodore computer drives),
• external speech synthesis device "RealVoice",
• removable ROM blocks with firmware (connected instead of a tape recorder).

The computer’s operating time from a single charge of batteries reached 50 hours, and consumed in idle current did not exceed 5 milliamps.

The later model, the TRS-80 Model 100 line, designed by Kyocera , inherited a lot from the HX-20.