Does anyone know where I can get some plotter free-ware / software? I'm trying to use an old hp 7550 plus, over the com-port and having trouble finding something to plot .dxf files. The plotter works, I have tested it using trial software that expired.

I use Autocad and a HP 7585B pen plotter from the serial port but had to make a support call at £25 to get the pin out serial to parallel then tryed a number of the built in drivers before I got one that works great.I would think that the pinouts would be common to the age of plotter. I think the plotter runs using HPGL I could send you the pin out diagram if its any help (free)

I have the serial port cable. It works. I used it with plotter sign software that expired and wants me to pay hundreds of dollars to continue to use something I play with for about an hour a month.

try www.signgo.com (http://www.signgo.com)

it's only 30 days, but it's a start.

I use Autosketch by Autodesk. I'ts the cheapest version of Autocad. Very good software, not free, but cheap for the capability.