[[File:NoPicture.png|100px|left]]
* '''First 464 Keyboard Circuit (PCB)'''
* Printed-circuit-board with wire-cables.
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[[File:NoPicture.png|100px|left]]
* '''Second 464 Keyboard Circuit (CPC664-style single-foil)'''
* Single "membrane" foil (with 19pin connector)
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* '''Third 464 Keyboard Circuit (CPC6128-style dual-foil)'''
* Two membrane foils (with 2x10pin connector)
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* Connections are closed when the key presses the two foils against each other.
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[[File:Nightfallcrew CPC Plus keyboard membrane.jpg|380px|left]]
* '''CPC Plus Keyboard Membrane'''
* Two membrane foils (with 2x10pin connector)
* Same as in CPC 6128, but with connection cable at rear side.
'''Keyboard / Case Dimensions'''
* CPC Plus - 398x297x46 mm (according to 464+/6128+ service manual)
* GX 4000 - 250x184x44 mm (according to 464+/6128+ service manual)
* KC Compact - <span style="color:#ff0000">399x218x43/54 </span> mm (serviceanleitung) <span style="color:#ff0000">or 388x218x43/54</span> mm (gerätebeschreibung) (?) <span style="color:#ff0000">or 3388x218x43</span> mm (!)(www.robotrontechnik.de and www.ddr-rechentechnik.de) (???)
* Aleste 520EX - <span style="color:#ff0000">???x???x??</span> mm