---
title: Casio PB-300
categories:
- Computers
types:
- Pocket
origins:
- Japan
years:
- '1983'
cpus:
- HD61913 CMOS VLSI
params:
  name: PB-300
  image: /media/museum/photos/casio_pb300_system_s1.jpg
  company: /companies/casio
  company_name: Casio
  specs:
  - label: NAME
    value: PB-300
  - label: MANUFACTURER
    value: Casio
  - label: TYPE
    value: Pocket
  - label: ORIGIN
    value: Japan
  - label: YEAR
    value: '1983'
  - label: BUILT IN LANGUAGE
    value: BASIC interpreter
  - label: KEYBOARD
    value: QWERTY calculator type 54 keys with numeric keypad
  - label: CPU
    value: HD61913 CMOS VLSI
  - label: SPEED
    value: 455 kHz, ceramic resonator used as system clock
  - label: RAM
    value: 2 KB (1568 bytes for BASIC)
  - label: ROM
    value: 12 KB
  - label: TEXT MODES
    value: 1 line x 12 chars plus a 4 digit seven segment display part
  - label: GRAPHIC MODES
    value: None
  - label: COLORS
    value: Monochrome LCD
  - label: SOUND
    value: None
  - label: SIZE / WEIGHT
    value: 173 (W) x 90 (D) x 20 (H) mm / 258 g (with batteries)
  - label: I/O PORTS
    value: 12-pin expansion port for cassette interface
  - label: POWER SUPPLY
    value: |-
      2 x CR-2032 lithium batteries\
      Integrated NiCd batteries for printer. External charger CHA-1 (4.8V/4.1W)
  - label: PERIPHERALS
    value: FA-3 cassette interface
  - label: PRICE
    value: Unknown
  tabs:
  - photos
  - links
  photos:
  - title: FRONT PANEL
    subtitle: ''
    text: ''
    image: /media/museum/photos/casio_pb300_frontpanel_s1.jpg
  - title: INSIDE
    subtitle: ''
    text: The bottom card is dedicated to the printer management and battery charging.
    image: /media/museum/photos/casio_pb300_inside_s1.jpg
  links:
  - title: Silrun Systems
    url: http://www.silrun.info/
    text: Documentations to download for Casio pockets ! Useful.
  - title: The Pocket Computer Museum
    url: http://pocket.free.fr/
    text: The site to visit for pockets computers !
  comments:
  - author: Dylan (USA)
    date: Saturday 16th March 2013
    text: I want a Casio PB-300. My uncle had one and I broke it as a kid. I want to surprise him! I can pay about $50 or so. Write to me at 4dylansmart at Google dot com
  - author: freddy (us)
    date: Sunday 23rd September 2012
    text: i have two for sale, one turns on, one doesnt
  - author: Carl (United States)
    date: Tuesday 18th September 2012
    text: I would like to buy a Casio PB-300 so I can sit at home and remember the early days. Anybody have one I can buy?
  - author: Harry Caswell
    date: Monday 15th November 2010
    text: |-
      I have a Casio PB-300 in the closet with manual,\
      would any one be interested in making an offer?
  - author: Fröbrich (Germany)
    date: Wednesday 21st July 2010
    text: I have a german user manual. It''s called "Casio PB-300 PROGRAMMIEREN LEICHT GEMACHT". But it is about 300 pages and not scanned. I am able to scann you a few pages, but not all.
  - author: A, brown (scotland)
    date: Saturday 24th April 2010
    text: I HAVE A PB-300 BUT NO INSTRUCTIONS CAN ANYONE HELP.
  - author: Allan Chinchilla (Cuernavaca, Mexico)
    date: Sunday 18th April 2010
    text: |-
      I have a PB300, will be possible to get a user manual?\
      Thanks. Allan
  related:
  - /museum/casio-fx-700p
  - /museum/casio-fx-702p
  - /museum/casio-pb-100
  oc_id: 1014
  source:
    url: https://web.archive.org/web/20230605040059/http://www.old-computers.com/museum/computer.asp?c=1014
    date: '2023-06-05'
---

Basically, the PB-300 was a [PB-100](/museum/casio-pb-100/) with more RAM and a built-in thermal printer. To our knowledge, Casio was the only company who designed real pocket size computers with integrated printers.

Of course, the PB-300 was substantially larger than its elder brother, therefore the keyboard could be laid out more generously, with a real space bar and an additional key for paper feed.

Due to the different physical dimensions, the main PCB had a different layout. However, the logic circuits were identical to the PB-100, with an additional HD61914 RAM chip. No further RAM expansion was made available.

As printers needed much more energy than the computer components, a 4 x 1.2V NiCad battery pack had to be integrated, which needed to be charged with an external power adaptor. The necessary printer and battery charging circuits were built onto a second PCB.

The printer used thermal paper of 39 mm width and was able to print 20 characters per line, making printed listings a little bit more legible than on the 12-character display.

To sum up, the PB-300 was a really cute machine. Imagine taking it with you in 1983 and impressing your friends by printing business cards when needed.

The PB-300 was also sold in Europe under the name Olympia [OP-644](/museum/olympia-op-544-op-644/).

Thanks to **Roman von Wartburg** ([retrocomputing.ch](http://retrocomputing.ch/)) for information and pictures.