I am getting this problem: When connecting a device to port COM1 (built in) and using Instrument I/O express VI, I am able to communicate with the device. However when I connect the same device to COM3 or COM4 (on an additional card), I am not able to communicate.
The card has been added because I need 3 COM ports, but I have tried with two different cards and still get the same result. The port are detected by Windows (it says they should work properly) and Labview (ports COM3 and COM4 are available in the list). Settings for all the ports are the same. Could someone explain me how I can fix this problem? Thanks
