Example: 
You should set the 4 or 8 COMs manually. 
The PCM-3643's setting: 
vector address 280H 
base address 300H 
S1 [(1) ON] [(2) ON] [(3) ON] [(4) OFF] [(5) ON] [(6) OFF] [(7) OFF] [(8) ON] 
S2 [(1) ON] [(2) ON] [(3) ON] [(4)  ON] [(5) ON] [(6) OFF] [(7)  ON] [(8)  ON]
IRQ: 5

You must add com3-com10 manually in winXP device manager or windows 2000 Add hardware Wizard. 

Windows XP:
Run "Hardware Wizard": 
From the Windows XP display, click "Start" and with right mouse click over "My Computer": 
Choose "Properties". 
Choose "Hardware". 
Run "Hardware Wizard" 
Choose "Add a new device". 
Choose "Select from a list". 
Choose "Ports". 
The resource IRQ=5(for com3-com10) 
address: 
com3:300-307 
com4:308-30f 
com5:310-317 
com6:318-31f 
com7:320-327 
com8:328-32f 
com9:330-337 
com10:338-33f 

Windows 2000:
From the control panel run "Add/remove hardware".
Choose "Next"
Choose "Add/Troubleshoot device"
Choose "Add a New Device"
Choose "No, I want to select the hardware from a list"
Choose "Ports (Com & LPT)"
Choose "(Standard Port Types)" & "Communications Port"
Windows will say that it can not detect the resources for the hardware you are trying to Add, and ask you to put in the Resources manually.
In the dropdown box next to "Settings based on:" Select the basic configuration at the bottom of the list. "Basic Configuration 0017"
this will fill in the IRQ and Base address with "?"
Replace the ? with the proper value by double clicking on each item. 
Repeat for each serial port on the module.