Amiga keyboards do not use the same protocol as PC keyboards; however, some A1200 keyboard adaptors support both A4000/A2000 keyboards and PC ones, so check if yours supports them.
I was under the impression that it was easy to wire up an A4000 keyboard socket to an A1200 motherboard, and a quick look on aminet confirms that it is pretty simple, and the parts to do it should cost very little, with one problem. Apparently the A1200 and A4000 handle keyboard reset slightly differently, and it requires a little extra work to get that to work.
All the instructions you need are in the hard/hack directory on aminet.
