Thanks guys! I apprecaite all of your help.

I was able to pull up a Toshiba document using the information Newtecky supplied. It said Toshiba started shipping the DK424 expansion cabinets in lieu of the DK280, in early 1997. So, the system in question has to be at least 10 years old since it has two DK280 cabinets.

That's what I needed to know. Thanks again.