After the MPF 2, compatible with the Apple II+, Multitech introduced the MPF3 in 1983 at the Las Vegas CES. It was compatible with the 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
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.
90 key, full stroke, internal conductive rubber membrane, 12+ function keys, numeric keypad
64KB DRAM + 2KB SRAM
40 x 24 / 80 x 24
40 x 40-48 (16 col), 280 x 160-192 (6 col), 560 x 160-192 (2 col)
1 bit Apple II compatible + AY-3-8912 Programmable Sound Generator. Internal speaker + External speaker jack
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)