Ok, specifically it is a TK50Z, an external box.
What's the difference?
It's been said that the 'non -GA' systems
aren't generic SCSI, but a DEC proprietization.
I have one both. The TK50Z-GA is the one that
has the SCSI ID selector on it, so the story seems
to jive.
Believe the -GA will work on 3100 and greater and
the -non will work on 2000's. Don't know for certain
yet.
John A.