PNC950 Help AGAIN!!!

For a few years I had this Roland workhorse working just fine with Corel. I didn't touch it for a few months and all of a sudden the computer wouldn't communicate with the plotter anymore... it just prints out a line of what looks like an internal code. I've tried every cable configuration, including a null modem it used to work with. I've reinstalled the print drivers as well. No luck. I recently got another Gerber software program and the Roland is in the selection list of plotters to install. I'm wondering if the Gerber program has a driver for the plotter built in? Might I now have two competing drivers installed? Any suggestions on what I might try next? I need this working for patterns for a line of hand lettered interior decor signs I'm designing for restaurants and bars a la Red Lobster.

 

Thanks a lot. This gives me a new approach to try. The plotter was set up as a printer for Corel when it was working fine and was attached to a null modem which I thankfully still have. I will try deleting the printer and selecting the plotter again in GSP setup. I figured they had a driver for it with the software. Now, all I have to do is try to figure out the HPGL thing also mentioned since Tony Teveris mentioned that to me too when I had this problem before.