Made in: USSR
A desktop version of Elektronika’s programmable MK-54, the MK-56 was released at the Elecon plant in Kazan in 1982. This was a second-generation programmable calculator with reverse Polish notation and a twelve-digit vacuum fluorescent display with eight digits for numbers. The device used 14 addressable memory registers and 98 programme steps, as with Elektronika’s MK-54 and MK-34. To save on memory space, developers greatly simplified the microcode, which resulted in endless error messages — a legacy from the earlier pocket models. Lots of data on these errors is now available on the web. The device had 30 keys divided into three groups, namely programming keys (left), numerical keys (centre) and memory-related keys (right), each with a dual function (toggled with the "F" key). All electric circuit components were hosted on two boards, with the first supporting an input device with a degree-radian-grad switcher and three key groups, and the second (core) hosting all the machine’s LSI circuits. The MK-56 ran on a 220V AC mains supply and, according to its developers, could be left on around the clock. One set of batteries lasted for more than 3 hours.