well, if ya really wanna know..there's a photosensor above the trays, and it measures the reflection or transparency..;) at least in the later model stuff..I don't know the details of the above, but it looks pretty similar to my training manuals..;) all good advice above..

Message edited on: 03/28/2006 21:22

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)