xp serial problem above com 9

Hi all,
I am having a problem with serial ports above 9.I have 9 serial port devices that I am using on a windows xp machine that works perfect and I now need to add 4 more serial devices to the same computer, com 10,11,12,and 13 but I am unable to get them working. (fail to open serial ports)

 

Welcome to WindowsBBS.

How are you connecting 9 serial devices ? Are these connected to USB to serial convertor or do you have a PCI card ?

 

Using usb serial devices.

 

Check out the website of your USB serial devices for the answer. Windows can handle any no. of serial ports provided your USB device handles it. What is the maximum number of serial ports for Windows XP.