The one Mike
has is definately the proprietary one (I also have one sitting
here). It was packed with scanners like the ScanJet Plus.
If that one is rare then the MCA version I use with the scanjet I have
must be unique! ;)
On the contrary, I have a scanjet (which I've never used) and the MCA adapter.
I have no machines with MCA, though (yet!), so I might be offering to buy the
ISA version. One day...
Philip.