website/content/museum/jupiter-cantab-jupiter-ace.md

---
title: JUPITER CANTAB Jupiter Ace
categories:
- Computers
types:
- Home Computer
origins:
- United Kingdom
years:
- '1983'
cpus:
- Zilog Z80A
params:
  name: Jupiter Ace
  image: /media/museum/photos/jupiter_ace_system_1.jpg
  company: /companies/jupiter-cantab
  company_name: JUPITER CANTAB
  specs:
  - label: NAME
    value: Jupiter Ace
  - label: MANUFACTURER
    value: Jupiter Cantab
  - label: TYPE
    value: Home Computer
  - label: ORIGIN
    value: United Kingdom
  - label: YEAR
    value: '1983'
  - label: BUILT IN LANGUAGE
    value: Forth
  - label: KEYBOARD
    value: QWERTY, chicklet keyboard, 40 keys, auto-repeat
  - label: CPU
    value: Zilog Z80A
  - label: SPEED
    value: 3.25 MHz
  - label: RAM
    value: 3 kb (up to 51 kb)
  - label: ROM
    value: 8 kb
  - label: TEXT MODES
    value: 32 columns x 24 lines
  - label: GRAPHIC MODES
    value: 64 x 48
  - label: COLORS
    value: Monochrome
  - label: SOUND
    value: Internal beeper
  - label: SIZE / WEIGHT
    value: 21.8(W) x 19.2(D) x 3.2(H) cm. / 246 g
  - label: I/O PORTS
    value: UHF TV out (channel 36), User Port, Tape interface (1500 baud), Z80 Bus
  - label: POWER SUPPLY
    value: External PSU
  - label: PERIPHERALS
    value: RAM expansion
  - label: PRICE
    value: £89.95 (UK, september 1982)
  tabs:
  - photos
  - adverts
  - hardware
  - software
  - emulators
  - links
  - docs
  photos:
  - title: JUPITER ACE
    subtitle: ''
    text: ''
    image: /media/museum/photos/jupiter_ace_system_2.jpg
  - title: TOP
    subtitle: ''
    text: ''
    image: /media/museum/photos/jupiter_ace_top.jpg
  - title: KEYBOARD CLOSE-UP
    subtitle: ''
    text: ''
    image: /media/museum/photos/jupiter_ace_keyboard_1.jpg
  - title: UNCOVERED
    subtitle: ''
    text: |-
      Note the large power regulator IC metallic cooler.\
      Keyboard membrane is simply put down on the board.
    image: /media/museum/photos/jupiter_ace_uncover_1.jpg
  - title: JUPITER'S HEART
    subtitle: ''
    text: |-
      The Jupiter design is very similar to the Sinclair ZX 80's one, except from the specialized component. Indeed you have to be sure to sell a great number of systems, if you want to be able to pay the development and production costs of such a component.

      **(1)** 5-volt power regulator\
      **(2)** Power jack. Power is supplied by an external AC adaptor\
      **(3)** Z80-A microprocessor. Here a Nec version\
      **(4)** Memory expansion connector. It is compatible with the Sinclair ZX 81 memory modules (up to 16 Kb). with a special adapter\
      **(5)** 2 x 4 KB ROM chips holding the FORTH programming language\
      **(6)** Buzzer\
      **(7)** 2 x 2114 static RAM chips holding 1 KB of RAM\
      **(8)** 4 x 2114 RAM chips hold 2 additional KB of RAM\
      **(9)** Peripherals connector, mainly used for printers\
      **(10)** Modulator for T.V. aerial video signal\
      **(11)** Tape recorder Load/Save jacks. Data transfer reliability is better than the Sinclair one.\
      **(12)** Keyboard contacts. When a key is pressed, a contact is made between 2 lines of the circuit
    image: /media/museum/photos/jupiter_ace_insideexpl_1.jpg
  - title: RUBBER KEYBOARD
    subtitle: ''
    text: The rubber keyboard and "eraser" keys need some practice for fast typing.
    image: /media/museum/photos/jupiter_ace_keyboard_2.jpg
  - title: BACK
    subtitle: ''
    text: |-
      Note the peripherals (left) and memory expansion connectors.\
      Grooves on the back cover are meant to avoid the thin plastic case bending out of shape.
    image: /media/museum/photos/jupiter_ace_back_1.jpg
  - title: LAST MINUTE
    subtitle: ''
    text: Last minute factory modification
    image: /media/museum/photos/jupiter_ace_lastminute_1.jpg
  adverts:
  - title: 'JUPITER BROCHURE #1'
    subtitle: ''
    text: ''
    image: /media/museum/pubs/jupiter_ace_brochure_s1.jpg
  - title: 'JUPITER BROCHURE #2'
    subtitle: ''
    text: ''
    image: /media/museum/pubs/jupiter_ace_brochure_s2.jpg
  - title: 'UK ADVERT #1'
    subtitle: ''
    text: ''
    image: /media/museum/pubs/cantab_jupiter-ace_pub1.jpg
  - title: 'UK ADVERT #2'
    subtitle: ''
    text: Thanks to [Howard Jones](http://wotsit.thingy.com/haj/) for this picture.
    image: /media/museum/pubs/cantab_jupiter-ace_pub_2.jpg
  - title: FRENCH AD (JULY 1983)
    subtitle: ''
    text: |-
      "access to the Forth power"

      "with the Jupiter Ace, enjoy profesionnal experience of Forth"
    image: /media/museum/pubs/jupiter-ace_pub_access-puissance.jpg
  hardware:
  - title: 16K RAM EXPANSION
    subtitle: from EME (Essex Micro Electronics)
    text: ''
    image: /media/museum/hardware/cantab_jupiter-ace_eme-16k.jpg
  - title: MEMOTECH KEYBOARD
    subtitle: ''
    text: Memotech, well known for making Sinclair extensions, also made Jupiter Ace accessories including this add-on mechanical keyboard.
    image: /media/museum/hardware/cantab_jupiter-ace_memotech-keyboard.jpg
  - title: EXPANSION BOARD
    subtitle: ''
    text: This board was used to plug more than one expansion to the Jupiter Ace.
    image: /media/museum/hardware/cantab_jupiter-ace_expansion-board.jpg
  screenshots:
  - title: SOME TAPES
    subtitle: ''
    text: ''
    image: /media/museum/software/cantab_jupiter-ace_software.jpg
  - title: TAPES, BOOK AND 16 KB RAM EXPANSION
    subtitle: ''
    text: ''
    image: /media/museum/software/jupiter_ace_soft.jpg
  - title: ATIC RAID
    subtitle: ''
    text: ''
    image: /media/museum/software/cantab_jupiter-ace_aticraid_ss.gif
  - title: BOMBER
    subtitle: ''
    text: ''
    image: /media/museum/software/cantab_jupiter-ace_bomber_ss.gif
  - title: FROGGER
    subtitle: ''
    text: ''
    image: /media/museum/software/cantab_jupiter-ace_frogger_ss.gif
  - title: LUNAR LANDER
    subtitle: ''
    text: ''
    image: /media/museum/software/cantab_jupiter-ace_lunar-lander_ss.gif
  - title: MILLIPEDE
    subtitle: ''
    text: ''
    image: /media/museum/software/cantab_jupiter-ace_millipede_ss.gif
  - title: PACMAN
    subtitle: ''
    text: ''
    image: /media/museum/software/cantab_jupiter-ace_pacman_ss.gif
  - title: WORDACE
    subtitle: Wordprocessor
    text: ''
    image: /media/museum/software/cantab_jupiter-ace_wordace_ss.gif
  emulators:
  - title: ACE32
    url: http://www.jupiter-ace.co.uk/ace32.html
    platform: MS DOS
    text: Jupiter ACE Emulator for MSDOS by Paul Robson
  - title: EightyOne
    url: http://www.chuntey.com/eightyone/
    platform: Windows
    text: The best Jupiter Ace Emulater for Windows platform , including AY8910 sound chip, colour board.The emulator of choice by the Jupiter Ace Archive team.
  - title: Blaze
    url: http://www.jupiter-ace.co.uk/blaze.html
    platform: Other platform
    text: Jupiter Ace Emulator for Sam Coupe computers
  - title: XACE, VACE and VACE3D Jupiter Ace emulators
    url: http://hem.passagen.se/tiletech/ace.html
    platform: Multiplatform
    text: Nice emulators by Edward Patel, for Windows and Unix. There is even a 3D version !!
  links:
  - title: Documentation
    url: http://www.jupiter-ace.co.uk/usermanual.html
    text: A searchable pdf of the manual, all 182 pages is now on the resource site at www.jupiter-ace.co.uk
  - title: Jupiter Ace FAQ
    url: http://users.aol.com/autismuk/ace/faq.htm
    text: FAQ written by Paul Robson.
  - title: Jupiter Ace Resource site
    url: http://www.jupiter-ace.co.uk/
    text: Jupiter Ace restoration and preservation project
  - title: The Jupiter Ace hardware page
    url: http://home.micros.users.btopenworld.com/JupiterAce/JupiterAce.html
    text: Helps you build your own Jupiter Ace !
  - title: The Jupiter Ace Software Library
    url: http://users.aol.com/autismuk/ace/software.htm
    text: Some software to download; useful !
  docs:
  - title: JUPITER ACE - USERS MANUAL
    url: http://www.jupiter-ace.co.uk/usermanual.html
    cover: /media/museum/docs/couvs/jupiter-ace_users-manual.jpg
    text: |-
      [**JUPITER ACE - USERS MANUAL**](http://www.jupiter-ace.co.uk/usermanual.html)written by Steve Vickers

       compiled/archived by Steve Parry-Thomas\
       type of document : PDF\
       source : [Jupiter Ace Resource Site](http://www.jupiter-ace.co.uk/)
  - title: THE FORTH BRIDGE - TRANSLATING BASIC PROGRAMS INTO FORTH
    url: http://www.jupiter-ace.co.uk/usermanual.html
    cover: /media/museum/docs/couvs/jupiter-ace_forth-bridge.jpg
    text: |-
      [**THE FORTH BRIDGE - TRANSLATING BASIC PROGRAMS INTO FORTH**](http://www.jupiter-ace.co.uk/usermanual.html)written by Jupiter Cantab

       compiled/archived by Steve Parry-Thomas / Jupiter Arce Archive Project\
       type of document : PDF\
       source : [Jupiter Ace Resource Site](http://www.jupiter-ace.co.uk/)
  - title: RAM PACK INSTRUCTION LEAFLET
    url: http://www.jupiter-ace.co.uk/usermanual.html
    cover: /media/museum/docs/couvs/jupiter-ace_ram-pack-instructions.jpg
    text: |-
      [**RAM PACK INSTRUCTION LEAFLET**](http://www.jupiter-ace.co.uk/usermanual.html)written by Jupiter Cantab

       compiled/archived by Steve Parry-Thomas / Jupiter Arce Archive Project\
       type of document : PDF\
       source : [Jupiter Ace Resource Site](http://www.jupiter-ace.co.uk/)
  comments:
  - author: Big Bad Bot
    date: Tuesday 22nd November 2016
    text: |-
      Jupiter Ace, when compared to computers of the era is just a little off center. And it is enough out of sync to make it uncomfortable to use$ especially since it did not have BASIC.

      Now if they created it as a color computer before the Spectrum, then it probably would have been more successful.
  - author: Jackson
    date: Sunday 10th February 2013
    text: I believe Matt is stupid and needs to get a life and typing lessons.
  - author: Matt Whele
    date: Monday 7th January 2013
    text: i believe all of you are stupid and need to get lives and get off of this site
  - author: Matt Whele
    date: Monday 7th January 2013
    text: i believe all of you are stupid and need to get lives and get off of this site
  - author: Matt Whele
    date: Monday 7th January 2013
    text: i believe all of you are stupid and need to get lives and get off of this site
  - author: Tony (Hastings/UK)
    date: Thursday 15th March 2012
    text: To keep comparing it solely to the ZX81 missed the point I think. Although memory was as low as the ZX81 and some of the hardware (such as graphics) almost as low, it was much closer in look and feel to the Sinclair Spectrum.
  - author: Nick (Swindon/Brussels)
    date: Saturday 29th May 2010
    text: I bought one in a sale at the time but it kept catching fire which was somewhat unnerving.
  - author: Steve(spt) (UK)
    date: Thursday 16th June 2005
    text: A searchable pdf of the manual, all 182 pages is now on the resource site at www.jupiter-ace.co.uk
  - author: Simon Goodwin (Warwick, UK)
    date: Saturday 6th December 2003
    text: |-
      The Jupiter Ace was designed and implemented by Steven\
      Vickers and Richard Altwasser after they left Sinclair\
      Research for their start-up company Jupiter Cantab.\
      As Altwasser designed the Spectrum hardware (and later\
      computers for Amstrad) and Vickers wrote the Spectrum\
      manual and adapted the ROM from that for the ZX-81\
      (as an employee of Sinclair's software sub-contractors\
      Nine Tiles) the family resemblance should come as no\
      surprise.

      Simon Goodwin (former Technical Editor of Crash magazine)
  - author: Mario Villar (Uruguay)
    date: Friday 15th August 2003
    text: |-
      I want to know if anyone out there has a Jupiter Ace manual that can send me via mail.\
      Many Thanks
  - author: Sam Wilson (Bergen)
    date: Wednesday 20th November 2002
    text: Well, this looks like an interresting computer. I have never had one, but i have run an emulator. This computer reminds me of the ZX Spectrum. Why are they so similair?
  - author: Alan Whiteside (UK)
    date: Wednesday 12th June 2002
    text: |-
      I have two Jupiter Aces which I have recently refurbished.I wonder if any one has a circuit diagram.

      Many thanks\
      AW
  oc_id: 147
  source:
    url: https://web.archive.org/web/20230529183420/http://www.old-computers.com/museum/computer.asp?c=147
    date: '2023-05-29'
---

The Jupiter ACE looks very similar to the Sinclair [ZX 81](/museum/sinclair-zx-81/). Actually, the designers of this computer, **Richard Altwasser** and **Steven Vickers**, played a major role in creating the Sinclair Spectrum.

The ACE is very similar to the ZX 81, but has some extra features: it has a user port, and it can generate sound (the ZX 81 can't). It can also use RAM expansion modules for the ZX 81 smaller than 64KB via a small adapter.

Its most significant feature is its language: instead of using BASIC like other computers, it uses the **FORTH** language (as did the [Hector HRX](/museum/micronique-hector-hrx/)).

FORTH's advantages are that it's comprehensible, small, interactive, fast and extensible. It centers around writing procedures which operate on objects on a FIFO stack, and is not as intuitive as BASIC. FORTH was three to ten times faster than BASIC but was not as easy to learn.

This computer did not achieve significant success, probably due to its relatively obscure language - as far as the general public was concerned.

Steve Vickers wrote the ZX Spectrum manual - he has been an academic researcher working most recently (2003) at Imperial College London, and the Open University.