My LabView work normally consists of developing a control application (on my office workstation) for a customer's system we are building, then installing the application as an executable on the customer's system PC.
I have had a problem with a system that required several serial ports. The system PC has an eight port PCI card installed in addition to the 2 integrated com ports. So the PC has COM1 through COM10 which all function fine when tested with Hyperterminal. The system design uses COM3, COM4, COM9 andCOM10 for various control and monitoring interfaces. When I developed the application on my workstation using VISA serial vi's, I had intended to hard-code the resource ID accordingly, which I typed in, because my office PC would only expose COM1 and LPT1 as available resources. When the application was installed, the COM10 port would not work. COM3, COM4, and COM9 functions communicated perfectly. Changing the hard-coded "COM10" to COM1 allowed the device formerly connected to COM10 work perfectly on COM1. This was programmed in LV 8.1.
I have done similar work in the past, using LV versions 5 & 6, using the older serial vi's that required serpdrv to use, and that would succesfully communicate with COM10.
For the moment, I am not dead in the water with this project because of the spare COM ports, but I haven't been able to find any reference that explains why COM10 wouldn't work. Please let me know if you can explain it, Thanks! I can post vi's if necessary, but they are pretty straightforward serial routines.