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Re: PS2 mini keyboard

Posted: Wed Feb 10, 2016 1:15 pm
by dilwyn
Martin_Head wrote:Just a thought, and sorry if I'm going a bit on the hardware side. But is it a case of the newer keyboards not supplying full 5 volt signals. maybe only 3, or a bit volts, which SuperHermes cant handle.

And all you need is a buffer IC to bring the signals back up to 5 volts. Just a little box that sits between the keyboard and SuperHermes, powered by the supply for the keyboard.

Martin Head
Thanks, sounds like a good idea.
As a good temporary measure I've found a stand which raises the computer enough and is wide enough for a normal sized keyboard to be able to slide in out of the way when not in use.

Re: PS2 mini keyboard

Posted: Mon Feb 27, 2017 10:16 pm
by Peter
Martin_Head wrote:Just a thought, and sorry if I'm going a bit on the hardware side. But is it a case of the newer keyboards not supplying full 5 volt signals. maybe only 3, or a bit volts, which SuperHermes cant handle.

And all you need is a buffer IC to bring the signals back up to 5 volts. Just a little box that sits between the keyboard and SuperHermes, powered by the supply for the keyboard.
I don't think so. PS/2 are open collector signals, bidirectional, and you have no access to a direction signal, so how would you buffer?

Also, I have doubts voltage is the reason. 3.3V supply is enough to satisfy TTL levels.

I'm using this keyboard on Q68 without problems.