---
title: Epson PX 4 / HC 40
categories:
- Computers
types:
- Portable
origins:
- Japan
years:
- '1984'
cpus:
- uPD 70008
params:
  name: PX 4 / HC 40
  image: /media/museum/photos/epson_hx40_1.jpg
  company: /companies/epson
  company_name: Epson
  specs:
  - label: NAME
    value: PX 4 / HC 40
  - label: MANUFACTURER
    value: Epson
  - label: TYPE
    value: Portable
  - label: ORIGIN
    value: Japan
  - label: YEAR
    value: '1984'
  - label: BUILT IN LANGUAGE
    value: Basic
  - label: KEYBOARD
    value: Full-stroke keyboard (chicklet keyboard available)
  - label: CPU
    value: uPD 70008 (Z80 compatible )
  - label: SPEED
    value: 3.6864 MHz
  - label: CO-PROCESSOR
    value: 'CMOS 7508 4bit : handles housekeeping, clock, battery, etc.'
  - label: RAM
    value: '64 KB : 64 Kbit CMOS D-RAM x 8'
  - label: ROM
    value: '96 KB : 256 K-bit CMOS ROM X 3'
  - label: TEXT MODES
    value: 40 x 8
  - label: GRAPHIC MODES
    value: 240 x 64
  - label: COLORS
    value: Monochrom LCD display
  - label: SOUND
    value: Beeper
  - label: SIZE / WEIGHT
    value: A4 size
  - label: I/O PORTS
    value: Serial, RS232c, cassette, cartridge port, printer (parallel) port, expansion port, sound in & out
  - label: BUILT IN MEDIA
    value: Microcasette
  - label: OS
    value: CP/M with disk-drives units
  - label: POWER SUPPLY
    value: Built-in battery which can last for 4 hours
  - label: PERIPHERALS
    value: Printers, plotters, tape-recorder, ROM & RAM expansion, barcode reader, EPROM burner, replacement keyboard, modem and more...
  - label: PRICE
    value: 1590 FF (France, january 1988)
  tabs:
  - photos
  - hardware
  - links
  forum_thread: 371
  photos:
  - title: JAPANESE USER MANUAL
    subtitle: ''
    text: |-
      Hello sweety !

      Thanks to the [TATA EPSON HC-40 Page](http://page.freett.com/tata93/hc40.htm) for this picture.
    image: /media/museum/photos/epson_hc40_manual_p1.jpg
  hardware:
  - title: EPROM WRITER CARTRIDGE
    subtitle: ''
    text: Epson H415A-EA1 Prom Writer Cartridge II. It plugged into the corner expansion port of the PX-4 and had a 32pin ZIF (Zero Insertion Force) socket.
    image: /media/museum/hardware/epson_px8_promwritermodule_1.jpg
  - title: EXPANSION SKETCH
    subtitle: ''
    text: |-
      There are for sure a lot of peripherals available for the HC-40 ! Wow...

      There are printers, plotters, RAM & ROM expansions, disk-drives, EPROM burner, barcode reader, keypad, etc...

      A larger and better picture is available at the [TATA EPSON HC-40 Page](http://page.freett.com/tata93/hc40.htm).

      Thanks to the [TATA EPSON HC-40 Page](http://page.freett.com/tata93/hc40.htm) for this picture.
    image: /media/museum/hardware/epson_hc40_expansion-sketch.jpg
  links:
  - title: Epson PX4 info page
    url: http://www.discordia.org.uk/px4/
    text: Pinouts and CP/M command reference among other things
  - title: TATA EPSON HC-40 Page
    url: http://page.freett.com/tata93/hc40.htm
    text: Great informations here (Japanese) !
  oc_id: 370
  source:
    url: https://web.archive.org/web/20230608211026/http://www.old-computers.com/museum/computer.asp?c=370
    date: '2023-06-08'
---

This computer is the successor of the [HX-20](/museum/epson-hc-hx-20/).

The main cosmetic difference is a wider screen that can be adjusted to the right angle.

There are 2 ROM slots under the machine to implement additional ROM programs.

On the right of the LCD display can be plugged a tape-recorder, a plotter, RAM expansions, a lot of things or ... nothing.

A lot of peripherals were available for this little computer (see hardware page), at least in japan.

The PX-4 was logically followed by the [PX-8](/museum/epson-px-8-hc-88-geneva/).