Editing Nascom (section)

==Expansion==
Nascom defined an expansion bus, named NAS-BUS, allowing many other cards to be added to the Nascom. The Nascom 1 required a buffer board to generate the NAS-BUS; the buffer board was connected to a 43-way (42-way plus polarising slot) 0.1" pitch tinned edge connector on its PCB. The Nascom 2 generated the NAS-BUS directly on an 80-way (79-way plus polarising slot) 0.1" pitch gold-plated edge connector on its PCB.

NAS-BUS was initially proprietary but quickly superseded by the 80-bus. The standard size for these cards was 8"x8" in order to fit in a "standard" 8" rack. However, some boards were produced in other sizes. Other manufacturers (including Gemini and MAP80 Systems) produced their own 80-bus CPU boards, which allowed an entire non-Nascom system to be built. Gemini 80-bus systems were, for a while, used as an industrial process controller. [[British Cellophane]] used several to continuously monitor thickness gauges attached to plastic sheet production lines. An 80-bus compatible network card enabled both Nascom and Gemini computers to be used in office environments.