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Adapt old "Liberty"-keyboard to PS2 or USB?

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Masterchief79:
Hey guys,
I'm new to geekhack, so let me introduce myself: My name is Niklas, I'm 19 and coming from Germany.
A few days ago a friend of mine bought a Black Widow and told me about the whole mechanical-keyboard-thing (had no idea something like that existed till then). So, as you can't set a foot in this house without stepping on a CPU, a GFX card or a mainboard, I started to look around for old mech keyboards and I found one made by "Liberty" (no additional info there), hooked up to a "Liberty"-terminal (also no model number or something like that). Should be at least 15 years old, but the nice thing is: The keyboard already uses Cherry MX Black switches :)

So, first here are some pics (unfortunately, one keycap is missing):










So, my goal is to hook it up to my desktop PC (PS2 or USB, didn't decide yet). It's gonna be a project :)
The interface gives me a headache, I've never seen something like this. In the last picture, you can see the usage of the pins, for example the keyboard gets a straight +12V input instead of +5V or +3,3V as usual, although I believe you should be able to adapt that with appropriate voltage regulators. But I think it gets funny at the signal and data transfer-part, because I don't see any correlations to a USB interface. So, it's very probable I have to develop an own PCB with the voltage regulators and a microprocessor which I can program by myself to translate the keyboard signal into a USB-compliant one for instance - at least if I can't find another solution, maybe the signal is closer to USB or PS2 than I think.

I tested the keyboard on the terminal already, works awesomely. By the way, it would be also an advantage if I was able to change the programming of the keys themselves, because the layout is really something you have to get used to ;)

This is what I found on deskthority:

--- Quote ---WTF is that thing!!!

At a guess, there is...
CGND - case/shielding ground
S.P. - dunno, but possibly Signal Power? Solenoid Pulse? Why the dots when the other names don't use dots?
+12V - yup. Maybe just for a bell or solenoid? Or for an RS232 converter chip?
SGND - yup. Signal Ground, most likely.
KRXD - serial receive line.
KTXD - serial transmit line.

So, it has no clock signal. Just as RS232 serķal has no clock signal.

Not something my converter can cope with, I'm afraid!
--- End quote ---
http://deskthority.net/workshop-f7/xt-at-ps2-terminal-to-usb-converter-with-nkro-t2510-60.html

Just tell me what you think (despite the fact that I should definitely clean it). But beware, comments like "just go buy a Cherry G80" don't help much, I'm afraid. As I said, gonna be a project and I'm sure I can need the electrotechnical knowledge elsewhere afterwards. Even if I could get a mechanical keyboard much easier.

Greetings,
Masterchief79

Paranoid:
glad you found the conversation about it on deskthority ^^
seems like one big project if you can magage to get it to work. I  for one don't have to background to design, make and program my own controller so the best of luck to you for this project :) because it is indeed one cool little keyboard!

Masterchief79:
I try to check whether the keyboard interface is just a regular serial signal. Gonna plug it on my oscilloscope and check if the signals are identical. If so: Done! We have Serial - USB adapters at home. If not, I try to adapt 1 or 2 keys by using an standard evaluation board and write a code which translates the signal.
After that, I still may develop my own PCB because our eva boards just have a register of 25 keys i think. Also, that's a lot more fun. ^^

Edit: It was 4pm when is posted this. American forum? xD

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