Well the mystery is pretty deep. Is it possible for an "ID Plug" to be bad? Using the DUP code on the KFQSA I set the UNITNUM on one of the RF71's to '1'. When I put the ID plug with the '0' on it, in its slot, it still reports as DUA0, however if I set FORCEUNI to 0 using DUP then it reports as DUA1 even though the ID plug says 0. The weird thing is that only the drive with the ID 0 plug in its slot responds to the controller, but both are tested on power up. I'm guessing it has something to do with the controller since the darn ID plug is just a piece of plastic! Oh, and it turns out I have two versions of this controller. One has a flat four position switch, the other a right-angle switch that I can adjust from the back. The latter has 3 open jumpers in the center of the board and the former has one open jumper. Curious. --Chuck