Question about keyboards

["Ernest" <leucoplast@seanet.NOSPAM.com>]

I have an external keyboard that was used on a German A2 clone, and I was
wondering if there is away to use this keyboard in conjunction with a normal
(case mounted) keyboard. My idea was to (in theory) build a keyboard
splitting device that both the external and internal keyboards plug into,
that could be controlled by toggling a switch before turning the computer
on.

I don't have any idea of how to build a device like this but I was curious
to know if it could be done very easily? I have a similar ROM switching
device on an A2+, and it seems that if it could be done with a ROM, why not
a keyboard?

I was also wondering about the different keyboards used on the Apple II's
and clones. The Apple II and IIe have different keyboards, and the IIe
Platinum has the numeric keypad, etc. Then, some of the clones have numeric
keypads but no Open/Closed apple keys, or no keypad at all, etc.

My question is... what allows one keyboard to work on one system but not
another? Where is that controlled? I mean, if you can switch different
keyboards (simple and with numeric pads) between different clones, would you
be able to switch a IIe and Platinum IIe keyboard between each other? Are
these old clone keyboards controlled by the character ROM on the
motherboard, or by a chip on the keyboard circuit board? How does all this
work?

Thanks.

Ernest