They're very flexible and can handle complex situations. The truth is, though, they're overkill for the kind of stuff our clients do. The Etherlites are more appropriate since they cost less and the ports behave more like regular serial ports.

Our typical multiport client is a medical testing lab that runs either Hex or CIS software (and no other applications at all). These are LIS (Laboratory Information Systems) extended with results forms printing and electronic billing. The host/servers are all SCO Unix, though Hex is starting to deploy Linux. Typical usage of serial ports would be:

• 4 or 5 medical testing machines that download results to the LIS.
  
• 4 or 5 Wyse 60 terminals
  
• A barcode printer
  
• 4 or 5 dot matrix printers.
  
• 1 customer call-in modem.
  
• 3 call-out modems (fax, remote printing, billing)

Configuration is rarely changed and user interaction is quite simplistic. The two principle requirements are: no downtime; no lost data, ever.