IBM 43G2455 w/ "Prototopre"

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05 Aug 2019, 04:18

Had this keyboard for a little while now and finally have the chance to take some pictures. It has what people consider "prototopre" switches, which is just a name for the rubberdomes that brother used in their keyboards at the time. Similar to the original find by Haata viewtopic.php?t=4101, and even shares the same "E57888" number on the back. I assume Haatas keyboard was a prototype made in Japan and tested in the USA to test brothers domes which makes sense, as brother made a lot of IBMs switches and keyboards for the Japanese market. The keycaps are nice pbt dyesubs that were not done by IBM, but by Brother which is apparent as it's more purple instead of the deep black typically seen on IBMs keyboards. It works right out of the box using a ps/2 connector. Overall it's a pretty good keyboard if you can get over the yellowing, which was probably a cost saving measure as the casing materials differ from all of my model m keyboards. The switches are a little bit on the heavy side for my taste, but the key feel is nice for a rubberdome. If you have any questions I'd be happy to answer!
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01 Oct 2019, 11:56

This post helped me a lot when I bought same one on the other day. Thank you for your posting.

It’s quite interesting that IBM released “proto-topre” JIS keyboards. Very surprising to me.

The logo on the microchip is Hitachi’s. I haven’t seen Hitachi’s microchip in keyboard. Obviously, it’s so rare.

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02 Oct 2019, 21:55

Hi, I seem to be trolling through patents constantly now.. did anyone ever definitively show these were made by brother?

Does this proto-topre switch have any relation to the Topre "Condenser switch?" Specifically the slider with the large square area at the botton. ... old&page=1 ... B=&locale=

I think this particular patent may be conductive, but it appears to be a Topre switch without a return spring or a coilspring.

I guess these are probably just topre conductive patents and not necessarily these switches though... I see now why people think brother!

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