PC Keyboard Adapter , plug a USB Keyboard or mouse into a PS/2 port on the PC | eBay
5 Pin DIN to PS/2 Cable Adapter, 5 Pin MIDI Male to 6 Pin Mini Din Female Adaptor for Mouser AT Keyboard (5 Male To 6 Female) : Amazon.co.uk: Musical Instruments & DJ
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StarTech Replacement USB Keyboard to PS/2 Adapter F/M 1 x Type A Female USB 1 x Mini-DIN (PS/2) Male Keyboard - Hunt Office UK