--- title: Tesla PMD-85 categories: - Computers types: - Home Computer origins: - Czechoslovakia years: - '1985' cpus: - MHB 8080A params: name: PMD-85 image: /media/museum/photos/tesla_pdm85_system_s2.jpg company: /companies/tesla company_name: Tesla specs: - label: NAME value: PMD-85 - label: MANUFACTURER value: Tesla - label: TYPE value: Home Computer - label: ORIGIN value: Czechoslovakia - label: YEAR value: '1985' - label: BUILT IN LANGUAGE value: BASIC G cartridge - label: KEYBOARD value: Full stroke 77 keys - label: CPU value: MHB 8080A - label: SPEED value: 2,048 MHz (Xtal 18,432 MHz divided by 9) - label: RAM value: 48 KB (Mod. 1), 56 KB (Mod. 2A), 64 KB (Mod. 3) - label: ROM value: 4 KB (Mod. 1, 2A), 8 KB (Mod. 3) - label: TEXT MODES value: 25 lines x 48 characters - label: GRAPHIC MODES value: 288 x 256 dots - label: COLORS value: 4 (Black, White, Grey, Blink) - 8 for the PMD-85-3 - label: SOUND value: 1 channel - label: SIZE / WEIGHT value: 31.3 (W) x 26.5 (D) x 6.5 (H) cm / 1.915 kg - label: I/O PORTS value: Serial, Parallel - label: BUILT IN MEDIA value: None - label: POWER SUPPLY value: Exxternal power supply unit, +5V, +12V, -5V, Max 35VA - label: PERIPHERALS value: Tape recorder - label: PRICE value: Unknown tabs: - photos - hardware - emulators - links forum_thread: 713 photos: - title: PMD-85-3 LARGE VIEW subtitle: '' text: Thanks to **Jan Krupka** for the PMD-85-3 pictures image: /media/museum/photos/tesla_pdm85_system_s3.jpg - title: COMPLETE SYSTEM subtitle: '' text: With the ROM module and the PMD-10 power supply unit. image: /media/museum/photos/tesla_pdm85_system_s4.jpg - title: REAR PANEL subtitle: '' text: |- From left to right:\ • Tape recorder DIN socket\ • Serial V24 DIN socket. The PMD-85/3 had a special terminal mode allowing it to be connected to SMEP and RVHP (PDP-11 compatible) mainframes\ • IMS-2 (IEEE 488) connector\ • Universal parallel bus 0\ • Universal parallel bus 1\ • General I/O connector. image: /media/museum/photos/tesla_pdm85_rear_s1.jpg - title: ROMS MODULE subtitle: '' text: '' image: /media/museum/photos/tesla_pdm85_romexpansion_s1.jpg - title: POWER SUPPLY UNIT subtitle: '' text: |- It fits perfectly to back of the computer but unfortunately the design was not so great if you want to connect something to the I/O port. In that case it simply lays somewhere around.\ Early PMD-85 wasn't shipped this unit, a standard PSU providing +/-5V and +12V was used. image: /media/museum/photos/tesla_pdm85_pmd10module_s1.jpg - title: INSIDE THE PMD-85-3 subtitle: '' text: |- The electronics od the PMD-85 consists of a logic card and an I/O card. **(1)** MHB 8255 for parallel interfaces\ **(2)** MHB 8253 timer\ **(3)** MHB 8251 USART, serial communication controller\ **(4)** 64 KB RAM chips\ **(5)** MHB8080 - CPU\ **(6)** MH 8228 - bus controller\ **(7)** 8 KB ROM chips\ **(8)** MHB 8255 - keyboard controller\ **(9)** Keyboard connector\ **(10)** Composite video output\ **(11)** TV RF modulator and output\ **(12)** External power supply connector. image: /media/museum/photos/tesla_pdm85_inside_s1.jpg - title: TESLA LABEL subtitle: '' text: '' image: /media/museum/photos/tesla_pdm85_label_s1.jpg hardware: - title: KZD01 TAPE DRIVE subtitle: '' text: |- This "intelligent" tape drive was mainly used with the PMD-85 as well as some other Czech computers.\ A special driver EPROM had to be installed inside the PMD program module.\ It used standard cassettes which must be "formated" before first use. Then it was possible to write or read from the drive. Sectors number identification allowed a direct access to the files. Thanks to **Jan Krupka** image: /media/museum/hardware/tesla_pdm85_tapedrive_s1.jpg - title: SP-210T CASSETTE DECK subtitle: '' text: |- Despite its Japanese style, this cassette deck was designed and made by Tesla. It featured an advanced cassette deck as well as a slow (1 needle!) dot matrix printer.\ The SP-210 was same model but without the printer. image: /media/museum/hardware/tesla_pdm85_cassettedecksp210_s1.jpg - title: ARITMA MINIGRAF 0507 subtitle: A4 plotter text: |- This small A4 plotter was widely used together with the PMD-85 as well as the IQ-151. In both cases it needed a special driver in EPROM.\ For use with PMD there was a set of EPROMs which must be inserted into the ROM module together with BASIC and monitor EPROMs. The Minigraf was connected to one of the multipurpose I/O ports.\ Later it was possibe to buy the Minigraf in some shops. There were also interfaces from Aritma for Atari XL and XE and for ZX Spectrum. Thanks to **Jan Krupka** for information and pictures image: /media/museum/hardware/tesla_pdm85_aritmaplotter_s1.jpg emulators: - title: PMD-85 emulator url: http://www.kmit.sk/~peto/ platform: MS DOS text: Written Peter Chrenko (download includes games) - title: PMD 85 czech Emulator url: HTTP://WWW.SCHOTEK.CZ/PMD/PMD85V13P.ZIP platform: Windows text: Other emulator - title: PMD 85 emulator url: http://pmd85.djb-studios.com/ platform: Windows text: pages of win32 emulator of PMD 85 and compatibles - title: PMD-85 emulators url: http://www.schotek.cz/pmd/indexe.htm platform: Windows text: DOS and various Windows versions. - title: PMD-85 v2 emulator url: http://pmd85.djb-studios.com/?module=dwl&did=1 platform: Windows text: new version / developed by RM-TEAM - title: PMD-85 win-emulator beta url: http://dev.djb-studios.com/cache/pmdemu_v1.4b.zip platform: Windows text: Written by Roman Borik & Martin Borik (include many progs and games) - title: PMD 85 hardware simulator/emulator based on AVR ATmega8515 with TV(PAL) output url: http://www.kmit.sk/~peto/AVR/smallpmd/index.php platform: Other platform text: Nice PMD-85 clone links: - title: Martin Schotek PDM-85 page url: http://www.schotek.cz/pmd/indexe.htm text: Complete description of various PMD-85 versions (in English). oc_id: 730 source: url: https://web.archive.org/web/20230608091452/http://www.old-computers.com/museum/computer.asp?c=730 date: '2023-06-08' --- The PMD-85 was a Czechoslovakian personal computer based on the MHB 8080A processor and manufactured by slovakian company Tesla Bratislava. Several versions were available:\ \- **PMD-85-1** (most common)\ \- **PMD-85-2** (better keyboard and software)\ \- **PMD-85-2A** (new motherboard)\ \- **PMD-85-3** (new motherboard again, pictured)\ \- **Mato** (kit of a clone in a smaller case) This machine was well known among kids and fans for its presence in schools in 80's. Thanks to **Monty Jack** and **Jan Krupka** from Czech Republik for info and picture. --- The PMD series, by **Andrej**\ Actually PMD series started much earlier. First one was **PMD-81** (from 1981) followed by **PMD-83** (of course manufactured in 1983-84) and the last one from series was **PMD-85**.\ While PMD-81 (as far as I know) had just cartridge for Basic G, PMD-85 had as standard Basic G, but also Pascal cartridge was available.\ Computer didn't have a monitor, it was plugged in regular (at that time B/W) TV.\ While PMD-85-3 had prominent keyboard (as you can see in a picture), previous models had flat keys Some acid remarks from **David Cady**:\ In fact, this computer did not have a built-in language. That Basic G was a kind of a cartridge or a module, that can be seen and identified fairly easy on the picture provided on the page.\ Above the keyboard, where the upper part of the rear panel begins, you can notice a slightly different colour of the case (the gray is a little lighter) with only one inscription on it in the upper right corner. Well, it's not the case anymore - it's that module! It was huge (in comparison to Atari or Commodore cartridges), quite heavy (almost one fifth of the total weight of the computer) and, surprisingly, fragile. Probably therefore was this Basic G module shipped automatically with the computer (plugged in already - that might be the reason, why it's so often described as built-in). Basic G was really bad, it was a very-low-performance clone of the Sinclair ZX Spectrum Basic programming language. Just imagine, that holding down the function key and pressing a letter key meanwhile wrote the whole command on the screen although there was no indication for the upcoming command on the keyboard itself (unlike ZX). It was very uncomfortable to get used to this and majority of those, who worked with PMD's didn't use this "fast commands writing feature". The PMD 85/1 had a pretty miserable keyboard made of telephone keys (!). Writing a couple of A4's could become a blood-sweating experience. PMD's were not really much cheaper in comparison to Atari, Commodore or ZX Spectrum computers (some of the peripherals were even more expensive than their 'western' equivalents), but they were the "official" computers for youth educating in computer science. Probably every other computer or programming club had several of those, so they became fairly widespread despite the quality. PMD 85/2A, PMD 85/3 and Mato, Slovak successor to (and clone of) PMD 85/2, were basically the same shit. Sorry to say that, but I had to work with them, so I know, what I'm talking about. I didn't like ZX's, but I'd prefer them anytime to PMD's. The peripherals - similar to ZX, any casette player/recorder could be plugged in. There was a special peripheral from Tesla that combined the tape recorder with a printer (the D-100 model or the BT-100 model). This printer had a single-pin head and you had to put a carbon paper (!) in between the head and the clean paper for the printer to work correctly - to print at all! That's what I call innovative approach :-)