Unfortunately I am not good with electronics. Fix anything physical, yes. Electronics mostly gobbledy goof.
The serial port instructions in the manual are complicated as the gates of hell. Parallel has only one choice to make so I always ran it as parallel. The first problem with parallel was that my new laptops did not appear to recognise the adapter and if they did they still did not offer "Parallel port" as an option so the software could not send a signal to the adapter.
Apparently most of the adapters don't have a time delay so the plotter is overwhelmed by the speed of the download.
I tried the technical dept at Roland but they were vague on old plotters and mostly only could help with music equipment!
My software (Visual Cadd V) seemed to have built in driver originally. Just load it and click "Plot." I am beginning to think that the only way to get this to work is to buy an old desk top with a parallel port and Windows 7, install my drafting program and transfer files on a USB stick! I don't really want to spend that kind of money unless I'm sure it will work!