If you have found this post, you are probably beating your brains out trying to figure out how to get your plotter to start cutting with your Mac. In this particular situation, I was using Signcut Productivity Suite. I had everything installed, but I could not get my mac to talk to my plotter. The little thing that nobody tells you is that you have to download the COM port driver here. Make sure that you download the one for the newer Intel Mac (if thats what you are using), install the driver, reset your computer and try again.