The 1801 series CPUs were a family of 16-bit Soviet microprocessors based on the indigenous Elektronika NC [ru] microarchitecture cores, but binary compatible with DEC's PDP-11 machines.

This machine, intended to directly compete with SM EVM series, was first released in 1973 and used the bit slice 4-bit 587 CPU, sometimes called the first Soviet microprocessor ever.

It was essentially a microcontroller with 256 bytes of on-chip RAM, 2K ROM and other peripheral circuitry, still based on Elektronika NC instruction set, but compatible with a Soviet clone of DEC's Q-Bus that was already adopted as an industry standard — a first sign of things to come.

By its nature, Soviet industry was an extremely bureaucratic structure, so decision making process was often driven not by technical or economical considerations, but by the results of the games of influence between various organizations and officials.

While its staff had an aversion to copying and reverse engineering Western technology, many groups within the Ministry of Electronic Industry argued for it as a quicker and more secure way to meet the needs.

This sudden reorganization resulted in the abandonment of the Elektronika NC architecture (it continued only in CNCs based on an NC-1 machine, some of which are used up to this day) and the adoption of the PDP-11 compatibility as a MEI standard, a process sometimes called PDP revolt in Russian literature.