I have 3 IO Gear USB to Serial Adapters (with software). These are very nice, small, and expand the serial port capabilities of our modern laptops to meet your astro control needs. I've run all three of these off one USB port on both Windows 98 and XP Pro without problems. They sell for $32-37 each from online stores and closer to $40 at Fry's. I'll ship all three of them to you for $55.