website/content/museum/multitech-mpf-iii-312.md

---
title: MULTITECH MPF-III/312
categories:
- Computers
types:
- Home Computer
origins:
- Taïwan
years:
- '1983'
cpus:
- MOS 6502
params:
  name: MPF-III/312
  company: /companies/multitech
  company_name: MULTITECH
  specs:
  - label: NAME
    value: MPF-III/312
  - label: MANUFACTURER
    value: Multitech
  - label: TYPE
    value: Home Computer
  - label: ORIGIN
    value: Taïwan
  - label: YEAR
    value: '1983'
  - label: KEYBOARD
    value: 90 key, full stroke, internal conductive rubber membrane, 12+ function keys, numeric keypad
  - label: CPU
    value: MOS 6502
  - label: SPEED
    value: 1 MHz
  - label: RAM
    value: 64KB DRAM + 2KB SRAM
  - label: ROM
    value: 24 KB
  - label: TEXT MODES
    value: 40 x 24 / 80 x 24
  - label: GRAPHIC MODES
    value: 40 x 40-48 (16 col), 280 x 160-192 (6 col), 560 x 160-192 (2 col)
  - label: COLORS
    value: 16 maximum
  - label: SOUND
    value: 1 bit Apple II compatible + AY-3-8912 Programmable Sound Generator. Internal speaker + External speaker jack
  - label: I/O PORTS
    value: TV RF out (RCA), Monitor Out (RCA), External Speaker Out (3.5mm), Cassette In/Out (2x3.5mm), Printer (16 pin, male 2x8 0.1"), Keyboard (DE-9M), Joystick (DE-9F), External Slot 2 (Apple II 50 pin), Internal Slots 4/6/7 (50 pin, female 2x25 0.1"), 2x Floppy Disk (optional, Apple Disk \]\[ compatible)
  - label: BUILT IN MEDIA
    value: None
  - label: OS
    value: DOS 3.3, CP/M (with optional Z-80 card), ProDOS 8 (if patched)
  - label: POWER SUPPLY
    value: internal switch-mode
  - label: PRICE
    value: $699 (1984, Australia)
  tabs:
  - photos
  - adverts
  - hardware
  - links
  photos:
  - title: INSIDE - FRONT
    subtitle: ''
    text: Thanks to David Wilson for this picture
    image: null
  - title: INSIDE - RIGHT SIDE
    subtitle: ''
    text: |-
      From left to right:

      \- keyboard connector\
      \- joystick connector\
      \- expansion port

      The blue cable on the left is an extender for the Apple II 16 pin game socket.

      Thanks to David Wilson for this picture
    image: null
  - title: INSIDE - REAR
    subtitle: ''
    text: |-
      From left to right:

      \- external disk drive connectors\
      \- tape interface MIC & EAR connectors\
      \- printer interface\
      \- volume control knob\
      \- audio output\
      \- monitor video output\
      \- TV RF video output\
      \- power in cable plug\
      \- power on/off switch

      The short grey cable on the rear of the system attaches to the header on ther right hand side of the slot extender to give it the /DEVSEL & /IOSEL signals for the extra slots. This was a Multitech option.

      Thanks to David Wilson for this picture
    image: null
  - title: KEYBOARD
    subtitle: ''
    text: Thanks to David Wilson for this picture
    image: null
  - title: DIP SWITCHES
    subtitle: ''
    text: |-
      Here are the functions of the DIP switches found at the back of the system:

      DIP1 On = 80 column text display Off = 40 column text display (Apple II default)\
      DIP2 On = Epson/CP-80 printer Off = C.ITOH printer\
      DIP3 On = RF modulator CH3 Off = CH4\
      DIP4 On = 64KB RAM Off = 48KB RAM

      Thanks to David Wilson for this picture
    image: null
  - title: SLOT EXTENDER
    subtitle: ''
    text: |-
      This is a slot extender that plugs into slot 2 to give more Apple II compatible slots.

      Thanks to David Wilson for this picture
    image: null
  adverts:
  - title: AUSTRALIAN ADVERT (JUNE,1984)
    subtitle: ''
    text: |-
      Advert for MPF-III in June 1984 issue of Electronics Australia magazine.

      Thanks to David Wilson for this picture
    image: null
  hardware:
  - title: DOUBLE DISK DRIVE
    subtitle: from an Australian advert (june, 1984)
    text: Thanks to David Wilson for this picture
    image: null
  links:
  - title: ACER milestones
    url: http://www.global.acer.com/about/milestones.htm
    text: Multitech was the first name of ACER
  comments:
  - author: Jan Huizinga
    date: Monday 24th August 2015
    text: |-
      I had a MPF-III with two(!) floppy drives. It was basically my first computer.\
      I quickly found out that it wasn''t that compatible with Apple. So finally I found a real Apple 2 and printed out the ROM.\
      After wards I programed (byte for byte) an EEPROM and replaced the MPF-III ROM with the EEPROM.\
      System booted up as Apple and worked perfectly!\
      Nice memories!
  - author: Erich Strelow (Chile)
    date: Tuesday 29th January 2008
    text: Also have fond memories of this piece. I had it as a teenager and used mostly with DOS 3.3. The CP/M card allowed to run Supercalc and Wordstar. The included documentation had a brief but insightful chapter on 6502 assembly programming.
  oc_id: 289
  source:
    url: https://web.archive.org/web/20230605024009/http://www.old-computers.com/museum/computer.asp?c=289
    date: '2023-06-05'
---

After the [MPF 2](/museum/multitech-mpf-ii/), compatible with the [Apple II+](/museum/apple-ii/), Multitech introduced the MPF3 in 1983 at the Las Vegas CES. It was compatible with the [Apple IIe](/museum/apple-iie/) but, like the MPF2, had no real success.

The MPF-III was released in two versions. The initial one was the /312 which used PALs and LSTTL logic. Later the /327 version was released and this used MMU and IOU ASIC chips just like the Apple IIe. The /327 may also have had 128KB of DRAM on the motherboard (MPF-III computers do not have an Aux slot so cannot have memory added in this fashion).

Slots 1-7 were configured like this:

1 (virtual) Built-in Parallel Printer port - support for Epson, C-Itoh and CP-80 printers\
2 (external) accepts standard Apple II cards\
3 (virtual) Built-in 80 Column Card - Apple IIe compatible\
4 (internal) Reserved for optional Chinese Character Generator card\
5 (non-existent)\
6 (internal) Reserved for optional Floppy Disk Interface\
7 (internal) Reserved for optional Z-80 CP/M card

ProDOS did not work (unpatched) on the MPF-III/312 for two reasons:\
1\) Apple put a test in the ProDOS initialization code that looks for the string APPLE in the monitor ROM. The MPF-III ROMs did not have this string. A one byte patch to the PRODOS file fixed this.\
2\) The Apple IIe came in 3 memory configurations - 64KB, 65KB (with 80 column text card) and 128KB (with 64KB 80 column card). ProDOS checks for more than 1KB of Aux RAM and if it finds it, sets up a 64KB RAMdisk. The MPF-III/312 has 66KB which ProDOS takes to be 128KB and attempts to create the /RAM drive. Again, a simple patch to ProDOS fixes this.

An optional bus expander was released that plugged into Slot 2 on the right hand side of the unit plus a ribbon cable to a header at the rear of the to pick up the missing slotr select signals. This allowed up to 5 external cards (slots 2/3/4/5/7).

---

**Contributors**: David Wilson

**Sergio Luvoni** adds:\
This model was known as **Latindata MPF-III** in South America. Monitor had a green CRT. Because of a diferent memory map, it was not fully compatible with the Apple II. However, Apple's Z-80 expansion card worked and a double 5.25" floppy drives unit was also available.

Further information from **Mark Slabbert**:\
I purchased the MPF3 in 1984. Was a pleasure to work with. Most Apple software packages would work on it but some graphics related software would not. Had extra commands in Rom not found on Apple, i.e. Effect x which would generate sound effects from the on board audio chip.\
Never gave me trouble although the keyboard had the habit of losing letters when cleaned. Excellent documentation included with computer. Sold it in 1988 in working order. Very compact casing but was still able to modify circuitry to drive external devices off data bus.\
Fond memories.