![]() Pentagon-1024SL v1.x  | |
| Also known as | Пентагон | 
|---|---|
| Type | Home computer | 
| Release date | 1989 | 
| Media | tape, floppy disks, hard drives (depending on models) | 
| Operating system | Sinclair BASIC, TR-DOS | 
| CPU | КР1858ВМ1/3, Т34ВМ1, Z80A, B, H @ 3.5 MHz (7 MHz turbo mode) | 
| Memory | 48 to 4096KB (depending on model) | 
| Storage | tape, Beta 128 Disk Interface, hard drives (depending on models) | 
| Graphics | 256x192, 384x304, 512x192 monochrome | 
| Sound | Beeper, Covox, UltraSound (depending on model) | 
| Backward compatibility  | ZX Spectrum 128 | 
| Related | ATM (computer) | 
| Website | pentagon | 
The Pentagon (ru: Пентагон) home computer was a clone of the British-made Sinclair ZX 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]
Versions
- Pentagon 48K (1989 by Vladimir Drozdov)
 - Pentagon 128K (1991)
 - Pentagon 128K 2+ (1991 by ATM)
 - Pentagon 128K 3+ (1993 by Solon)
 - Pentagon 1024SL v1.x (2005 by Alex Zhabin)
 - Pentagon-1024SL v2.x (2006 by Alex Zhabin)
 - Pentagon ver.2.666 (2009 by Alex Zhabin)[3]
 
The Pentagon 1024SL v2.3 included most of the upgrades of the standard Spectrum architecture, including 1024 KB RAM, 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]

Upgrades from the original ZX Spectrum
- Extra RAM ranging from 256 KB to 4 MB
 - Several sound card possibilities such as Covox (usually named as SounDrive) or DMA UltraSound
 - Additional video modes: 512x192 monochrome, 384x304, 256x192x15 (with no Attribute clash)
 - CMOS with persistent real-time clock
 - IDE Controller for hard drives
 - "Turbo Mode" that clocks the CPU up to 7 MHz
 
References
- ↑ "Pentagon — SpeccyWiki". speccy.info.
 - ↑ "Russian Most Popular Spectrum Models". www.worldofspectrum.org. Archived from the original on 2012-07-16. Retrieved 2004-09-08.
 - ↑ "Информация". pentagon.nedopc.com.
 - ↑ "Pentagon — SpeccyWiki". speccy.info.
 
External links
- Russian most popular Spectrum models Archived 2012-07-16 at the Wayback Machine
 - Pentagon 1024 official site (in Russian)
 - Schematic diagram of the Pentagon 48K and drive controller (DjVu)
 - 128K Schematic diagram of the Pentagon (the DjVu)
 - Schematic and wiring diagrams Pentagon 128K 1991, revised and enlarged version (PNG)
 - Wiring diagram 128K the Pentagon (the PNG)
 - NEW English FaceBook Group
 

