I worked at this company for some 4 months last year on a project --->> http://www.comtrol.com/

They have all manner of methods to add loads of extra serial ports to a PC. Look through their WEB site and you can find PCI board solutions, ISA board solutions, USB serial hub solutions, and remote Ethernet serial hub solutions. Too many choices in fact!!

The center of their capabilities are some specialized hardware LSI chips they make that gives them 8 and 16 UARTS with FIFOs on one chip!! A typical PCI board for 8 ports consists of a PCI bus bridge chip, the custom LSI, and 8 sets of RS232 drivers. These all connect out the rear panel bracket to a multi ended cable dongle for the 8 ports.

By far the coolest product is the Ethernet attached product, called the DeviceMaster, which gives 8 or 16 ports per external box. You can stack up as many boxes as you want. All available from one or more network locations provided you have the PC bandwidth to field all the data from the huge mass of ports that are possible.

Michael Karas