While taking to a guy in the Pittsburgh PA area, he told me that he was having issues with a computer. Long story short he said that laptops were not good for running the software and machines he had. I then sent him 2 laptop computers that ARE equipted with a parallel port that successfully ran the software and his commercial equipment. The Pulse Freq rate is rock steady at 25,387. You can even run other software while the Mach3 CNC software is running. I did a demonstration on youtube for people to view if they'd like. http://youtu.be/YDlJl4OkZKg The reason I'm posting here is that I actually configured 3 of these computers for him but he only needed 2 of them (which he has had for several months now, running with no issues). Therefore I have 1 left. If anyone would like to purchase it, I would like to sell it. Contact me and make me an offer. I did not see a classified section on this forum site so I decided to post it here. PM me if you are interested.