We have have very good luck with USB/serial multifunction hubs from Entrega hub 2U4S. This unit has 2USB ports and 4 serial ports. This unit needs to be plugged in to 110v power so it needs to be on a UPS.
We buy them from Microwarehouse for $ 140.00, part # DEH4272 1-800-367-7080 (
www.warehouse.com).
We buy our dual port PCMCIA cards from Mobile Planet 1-800-675-2638 (
www.mobileplanet.com). Cards made by SOCKET work well and go by the part # MP540100 for $ 240.00
NOTE! Always decide which type of serial port system you want to use. Adding a USB hub after a Dual Socket card will work, but may be clumsy. The USB software creates "virtual" serial ports and assigns them based on what is already there. If there is a dual card present, the USB software will assign ports 5-8. You will then lose the usefulness of a couple of ports due to not being able to assign higher than Com 7 in Nastar*ware.
Fred Patton
fpatton@phoenix-sports.com