The Elektronika MK-85 was the world’s first 16-bit handheld PC with microprogrammed BASIC language. The microcomputer was developed by Zelenograd’s Research Institute of Fine Technology in 1985 and was commissioned by Alexander Shokin, the USSR’s Minister of Electronic Industry (lead designer — L. Minkin, deputy lead designer — Y. Otrokhov, developers — S. Yermakov, O. Semichastnov, B. Krotkov, A. Podorov, V. Gladkov, etc.). The device used a custom-made 16-bit KA1013VM1 microprocessor as its main large-scale Integration (LSI) circuit. The processor was compatible with the DVK and BK-0010 personal computers, both of which were held in high regard at the time. During this period, foreign manufacturers built their handheld PCs on 4 and 8-bit microprocessors.
While the calculator retailed for 115 RUB and was in short supply, over 150 000 thousand units were sold between 1986 and 2000.
The first models featured logos such as Programmable Calculator and Personal Computer, later changed to Microcomputer. The design and operating system were modelled on Casio FX-700P.
In 2007, issue 6 of the Electronics magazine published B. Malashevich’s comprehensive article on the unique microcalculator’s technical capabilities and history:
The MK-85 can be used in two modes: as a calculator or as a BASIC computer. Information and commands are typed on 54-key keyboard divided into two panels. The left panel features 35 multi-function keys that allow the user to input lower and upper-case letters of both Cyrillic and Latin alphabets, mathematical and special signs, commands and BASIC operators, while at the same time enabling the user to control the cursor and toggle modes for the calculator and its keys. The right panel has 19 single or multi-function keys for inputting numbers and several Russian letters, selecting a file from RAM, and performing a number of command functions. Multiple functions (up to seven) could be activated by the S and F combined function keys, as well as the MODE key (mode select). Function markings are located on, above, below and to the right of each key, and on a special keyboard overlay.
The inputs scroll horizontally for up to 63 symbols. The twelve-digit dot-matrix LCD with adjustable contrast can reproduce up to 12 letters, numbers and symbols at once. The arrow keys provide scrolling functionality. The upper part of the display shows the current mode and the number of remaining programme steps. To the right of the LCD, the mode table represents the only difference between the face plates of MK-85 and FX-700P — the absence of a PRT (printer) mode. As well as a keyboard and display, the front of the device has a power switch. The left side, unlike the FX-700P, has a slot for the Elektronika D2-10K line adapter that came with the MK-85.
Programming could be done with 1,221 programme steps and 26 registers. There was also Elektronika MK-85M, a modified model with increased programme memory (5,317 steps). The device had 64 kB of addressed memory and the maximum clock rate of 2 MHz.
Moderate power consumption (up to 20 mW) ensured seamless operation on batteries for 200 hours in the write and debug modes, and 80 hours in the calculation mode. The turbo mode (4x higher speed) consumes much more power, so it is better to use it with the line adapter.
In early 1986, the first Russian handheld PC — Elektronika MK-85/MK-85M — went on sale in the Elektronika brand shops of the Ministry of Electronic Industry. The 145-RUB asking price was high for the time, given that the starting monthly salary of a young engineer was between 90 and 130 RUB. Nonetheless, the MK-85 sold like hot cakes in Moscow, Leningrad, Voronezh and other cities.
As with the standard MK-85 models, there were lots of modifications. The MK-85, with its special firmware, was used in military aviation and artillery, and even for statistical research on student group behaviours.
Famously, the MK-85 was used to combat economic fraud. During the turmoil of the 1990s, Zelenograd’s Angstrem collaborated with Ankort on mods for Elektronika’s MK-85B and MK-85C models. The „B„ models were used in banking, while the “C" (Crypto) models were for cryptographic purposes. These MK-85 models had special firmware with powerful encryption algorithms, allowing for efficient coding of texts of up to 1,500 symbols. The widespread bank confirmation fraud was nipped in the bud thanks in part to the MK-85’s banking mods.
Elektronika MK-85 ran on four STs-0,18batteries or a D2-10K line adapter.
Dimensions: 13×166×73 mm
Weight: up to 150 g