---
title: Hewlett Packard HP-75C / 75D
categories:
- Computers
types:
- Pocket
origins:
- U.S.A.
years:
- '1982'
cpus:
- 8 bits
params:
  name: HP-75C / 75D
  image: /media/museum/photos/hp_75c_system_1.jpg
  company: /companies/hewlett-packard
  company_name: Hewlett Packard
  specs:
  - label: NAME
    value: HP-75C / 75D
  - label: MANUFACTURER
    value: Hewlett Packard
  - label: TYPE
    value: Pocket
  - label: ORIGIN
    value: U.S.A.
  - label: YEAR
    value: |-
      75C : September 1982\
      75D: 1984
  - label: END OF PRODUCTION
    value: |-
      75C : May 1984\
      75D : 1986
  - label: BUILT IN LANGUAGE
    value: Basic interpreter, Visicalc spreadsheet
  - label: KEYBOARD
    value: 64 keys. Each key is user-definable
  - label: CPU
    value: 8 bits, called Capricorn
  - label: RAM
    value: 16 KB
  - label: ROM
    value: 48 KB
  - label: TEXT MODES
    value: LCD display. 1 line x 32 chars.
  - label: GRAPHIC MODES
    value: 160 x 9 pixels
  - label: COLORS
    value: Monochrome
  - label: SOUND
    value: Beeper
  - label: SIZE / WEIGHT
    value: 25.4 x 12.7 x 3.2 cm. - Weight 737g.
  - label: I/O PORTS
    value: HP-IL, 3 x ROM/RAM expansion ports
  - label: BUILT IN MEDIA
    value: Memory cards, 1.3 KB
  - label: OS
    value: Specific
  - label: POWER SUPPLY
    value: Battery pack or external AC adaptor
  - label: PRICE
    value: '75C: $995 - 75D: $1095'
  tabs:
  - adverts
  - links
  forum_thread: 626
  adverts:
  - title: FIRST AD
    subtitle: ''
    text: February 1983 - The real-size system picture occupied almost the full right page.
    image: /media/museum/pubs/hp_75c_pub_1.jpg
  links:
  - title: Reverse-Engineering the HP-75C
    url: http://www.fortitudine.com/~coryc/html/hp75c.shtml
    text: Very informative page with useful & practical info such as keys functions, Basic commands and HP-IL operations
  - title: The Museum of HP calculators
    url: http://www.hpmuseum.org/hp75.htm
    text: This site has a nice and complete page about the HP-75C/D. You can even order the original manual.
  oc_id: 640
  source:
    url: https://web.archive.org/web/20230607231723/http://www.old-computers.com/museum/computer.asp?c=640
    date: '2023-06-07'
---

The **HP-75C** was the first pocket computer ever produced by HP who wanted a pocket book format (10”x 5”) computer as powerful as a desktop. It can also be considered as the first organizer able to deal with a multiple alarms time schedule, to control real time peripherals and to memorize text files.

Its 48KB ROM contained a very complete Basic language and a light version of the spreadsheet Visicalc. Three slots allowed adding pre-programmed ROM modules (Maths, finance, word processor…)

It integrated a card reader. The cards was manually slipped front of the magnetic head. Each card could stock 1.3 KB of information on 2 tracks (650 bytes each). The card information coding allowed great variations of the reading speed, due to manual handling.

The HP-IL (Interface Loop) interface allowed connecting as far as 30 peripherals simultaneously on the HP-75C. Amid the peripherals, one could find a display unit, printers, a modem, a tape recorder and all the HP-IL standard peripherals.\
As always with HP, the manuals were very complete and pedagogical.

The **HP-75D** was released two years later. It added a wand and wand port. When used with the Bar Code ROM, the computer could scan CODE11, CODE39, UPC, and EAN codes. This made the computer useful for inventory control.