I have a laptop compaq 17 xl 366, it has no db9 serial port, and I need to communicate with a plc 5/40 allen bradley using rslogix and 6200 softwares. How I can do it? I am not sure if any converter usb to serial port like the belkin's accesories can help me. I know that compaq make duplicator ports like quikdock, but I don't know if it is a good solution. I try to fix it, I buy a us pda adapter, used for palms and some mouses to communicate across usb pc ports. It works good with the mouse but not with the plc. Anyone know how I can fix it?