Editing Nintendo VS. System (section)

==Hardware==
The VS. System was designed primarily as a kit to retrofit ''[[Donkey Kong (arcade game)|Donkey Kong]]'', ''[[Donkey Kong Jr.]]'', ''[[Donkey Kong 3]]'', ''[[Popeye (video game)|Popeye]]'', and ''[[Mario Bros.]]'' cabinets, so they require the same special monitor. These monitors use inverse voltage levels for their video signals as compared to most arcade monitors.

Almost all VS. System cabinets have identical hardware powered by a [[Ricoh 2A03]] [[central processing unit]] (CPU), the same in the NES, except for special PPUs or video chips.<ref>{{Cite web |title=Nintendo Vs. UniSystem/DualSystem Chipsets |url=http://www.pc-10.com/vschipsets.html |access-date=July 30, 2017 |website=pc-10.com}}</ref> Each chip contains a different palette that arrange the colors in different configurations chosen apparently at random. Most boards can be switched to a new game simply by swapping the program ROMs and the appropriate PPU or the game will have incorrect colors.<ref>{{Cite web |title=Nintendo Vs. Unisystem Nintendo Vs. Dualsystem Arcade Manuals, PPU, PCB info, daughter board info, Nintendo Vs. Instruction Cards, game info |url=http://www.johnsarcade.com/nintendo_vs_ppu_info.php |access-date=July 30, 2017 |website=www.johnsarcade.com}}</ref> Several of the later units employ further copy protection by using special PPUs which swap pairs of I/O registers or return special data from normally unimplemented regions of memory, and games are not interchangeable with these models.

Some dedicated double cabinets look like two games butted together at an angle, with a single motherboard. The Red Tent, a steel sit-down cabinet for the VS. DualSystem, allows play for up to four players simultaneously. It has the same motherboard as the double cabinet.

Because the ''VS. System'' has the same CPU as the NES, its games can be ported to the NES with modifications to the console including extra memory banks and additional DIP switches.<ref>{{cite web |last=Assenat |first=Raphael |title=Modding a NES to run Unisystem VS arcade games (1/14) |url=http://www.raphnet.net/electronique/nes_vs/nes_vs_en.php?section_id=0 |website=www.raphnet.net}}</ref> Some games differ from their home console versions. For example, ''[[VS. Super Mario Bros.]]'' is considerably more difficult than ''[[Super Mario Bros.]]''; some of the levels were reused in ''[[Super Mario Bros.: The Lost Levels]]'' for the [[Famicom Disk System]].<ref>{{cite web |last=McLaughlin |first=Rus |date=September 13, 2010 |title=IGN Presents: The History of Super Mario Bros. |url=http://www.ign.com/articles/2010/09/14/ign-presents-the-history-of-super-mario-bros?page=3 |url-status=live |archive-url=https://web.archive.org/web/20150905204925/http://www.ign.com/articles/2010/09/14/ign-presents-the-history-of-super-mario-bros?page=3 |archive-date=September 5, 2015 |access-date=April 1, 2015 |work=[[IGN]] |page=3}}</ref> Some games' graphics differ, such as ''[[VS. Duck Hunt]]'' having more details and animation sequences.