Do you still have the data/messages from the old DL20 available to upload or in hard copy somewhre?
I beleive the DL20 software only comunicates through comm port one, maybe comm2.
These used to be abundant on ebay, but looks like someone has been snappping them up as fast as they come up. I had to replace one about 8 months ago and it was not cheap. If time had permitted, I'd have used some other HMI/display device, but something needed to be done now.
Check your PM messages.