...the use of a serial touchpad for control of an Empeg.

If you can program the serial touchpad to:

1. Work at either 4800 or 115200 BPS.

2. Work with no flow control.

3. Output a specific set of commands ...

Then one should just plug directly in.

If #3 there is not possible with the serial touchpad you want to use, then there's likely a way to write a piece of software or a kernel tweak for the empeg to respond to whatever it *does* output.

Interesting, but I wasn't thinking of anything so grand.

I was thinking more of the ancient method serial mice used to implement under DOS, where strokes were intrepreted as arrow keystrokes. Something as simple as repeated left right up down, this could allow for menu navigation. Also some of the touchpads like the Alps have a couple of buttons.