The Pentagon (ru: Пентагон) home computer was a clone of the British-made SinclairZX Spectrum 128.
It was manufactured by amateurs in the former Soviet Union, following freely distributable documentation. Its PCB was copied all over the ex-USSR in 1991-1996, which made it a widespread ZX Spectrum clone.
The name "Pentagon" derives from the shape of the original PCB (Pentagon 48), with a diagonal cut in one of the corners.
[1]
Many simple devices (upgrades) were invented to connect to the Pentagon with some soldering.[2]
The Pentagon 1024SL v2.3 included most of the upgrades of the standard Spectrum architecture, including 1024 KBRAM, Beta 128 Disk Interface and ZX-BUS slots (especially for IDE and General Sound cards). This model also featured a "turbo" mode (7 MHz instead of the original's 3.50 MHz).[4]
