
Appendix C Troubleshooting and CommonQuestions
PCI Serial for Windows Me/9x C-6 ni.com
Common QuestionsHow can I determine which type of serial hardware I have installed?
1. Select Start»Settings»Control Panel and double-click on the 
System icon.
2. Click on the Device Manager tab and click on the View devices by 
type button.
3. Double-click on the Ports (COM & LPT) icon to display a list of 
installed ports.
How can I determine which version of the NI-Serial software I have 
installed?
The ReadMe file gives the version of the software. To open the file, select 
Start»Programs»National Instruments Serial»ReadMe.
What do I do if the diagnostic test fails with an error?
Refer to the Troubleshooting Diagnostic Messages section earlier in this 
appendix.
How can I determine which port is associated with COMx?
To determine which physical port is associated with COMx, complete the 
following steps:
1. In the Device Manager tab, under Ports (COM & LPT), double-click 
on a serial port.
2. Click on the Port Settings tab to display the serial number of the serial 
hardware and the physical port number starting at 1. For all serial 
hardware, PORT1 refers to the top port, PORT2 refers to the next port 
down, and soon.
How can I change the COM numbers of my National Instruments 
serial ports?
To name serial ports COM1, COM2, COM3, or COM4, change the base 
address of the port. To do so, refer to the Selecting Conflict-Free Resources 
section earlier in this appendix.
When you change the base address, Windows Me/9x automatically 
converts it to the corresponding COM name listed in TableC-1. You do not 
need to change the IRQ setting for Windows Me/9x to change the name.