Two dead LK201 keyboards

Paul Koning paulkoning at
Sat Dec 28 10:27:35 CST 2019

> On Dec 28, 2019, at 5:25 AM, Pete Turnbull via cctalk <cctalk at> wrote:
> On 28/12/2019 01:46, Paul Koning via cctalk wrote:
>> I can get one and test it with an Apple keyboard, but that doesn't sound right.  There aren't enough wires on a USB connector to allow you to speak the PS/2 protocol.  And there are PS/2 to USB adapters (for old keyboards) that are the same size; clearly the old keyboards don't speak USB.
> Enough wires?  +5V, ground, clock, data vs +5V, ground, D+, D-
> Those old adapters are definitely just passive wiring, and were commonly supplied with dual-standard mice.  That's why they're green.  I worked in the IT department of a large university and it caused a lot of confusion back in the day when they were common, when people expected them to convert any keyboard or mouse to PS/2, and found they didn't. They only work with devices that inherently support both protocols.

Ok, it sounds like I jumped to conclusions on insufficient data.  It sure is amazing to speak two so unrelated protocols on the same wires and somehow make it work.


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