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

[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:

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!

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