IBM 1393915: An itsy bitsy input thingy

I have been unable to confirm it as such, but I’m reasonably confident that this is the PS/2-compatible 4704 emulation keyboard used on various period IBM personal computers when acting as a 4704.

It isn’t among the known part numbers for that system, though, and I have not yet verified what it expects to be connected to, interface-wise.

This is one of a handful of known keyboards (mainly if not exclusively, specialized function keypads smaller than a traditional keyboard) which uses the membrane buckling spring, but sandwiched in the style of assembly used for capacitive buckling springs instead. This enhances reliability/longevity, as failure of the plastic rivets can’t happen: there are none.

  • Identification: IBM part number 1393915, manufactured in USA by IBM 1989-09-14
  • Application: still figuring this out, suspect 4704 emulation on PC, PS/2 etc.
  • Connectivity: SDL connector, unknown interface
  • Key layout: 50-key matrix (grid) layout
  • Keyswitches: tactile and ‘clicky’ buckling spring over membrane
  • Acquired: February 2015, private sale online

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