Tony Duell wrote:
   Ooh - you
don't see many Atoms using the expansion bus for System cards (with
 the exception of the Disc Pack). 
 I think one of my other Atoms has one of the lab I/O cards mounted
 inside, connected to the system bus. 
 
 Didn't come from Cambridge uni originally, did it? :-) I had two from there on
No, most of my Atoms, including this one, came from Reading University. I
also got the System 4 that was used as the Econet file server.
  the bench just before I left for the US; both with lab
interface boards
 mounted in the bottom of the case. It's the first time I'd seen that actually
 done, although I believe that somewhere Acorn do mention as a feature the
 possibility of stuffing a System board in there... 
The bus pinout is identical, all you need is a length of ribbon cable
with the right connectors on the end.
-tony