I made some progress with dtp22 not working. It turns out that my problem was that I had PuTTY on at the same time I was trying to run spotread. I think there was a conflict in accessing the COM1 port. However, after I got that sorted out I ran spotread again. It asked for calibration. I calibrated. It asked for me to read a spot. I did that and got the following error message: "Got fatal error ‘Not expected instrument model’ (Instrument password was rejected)" So, I guess I have one of the oddball versions of the dtp22. Is there any way to find the password? My Unit is marked "ColorMark calibrator" on the top of the unit. On the box it says, "MacDermid GRAPHICARTS ColorSpan". On the bottom, just below the dtp22 label it says "E165006". I wonder if the "E165006" is the password or is somehow related to the password. Alan P.S. I haven't figured out how to add to a thread on freelists, so I apologize for starting a new thread on this.