On Thu, 19 Oct 2006, Chuck Guzis wrote:
  If you're thinking about a Catweasel-type external
box, then I'd put
 lots of memory (10 MB or more) and some programmable intelligence in
 it (so the "nuts and bolts" isn't subject to OS platform-related
 issues).  Maybe interface with something dirt-common, like RS-232C.
 Of course, this would push the price of a basic unit up pretty high. 
If you don't mind it being rather bulky, . . .
just start with an old AT.  Put in a lot of RAM (up to 16M on 286 or
386SX), a catweasel, a serial port, and some relatively trivial software.
The catweasel is the only part that will cost more than a burger.