I have an older NI 2 port RS-485 PCI card (c. 1997). Recently I neede to configure port 1 for 2 wire and port 4 for 4 wire. Using Windows 7 and the latest version of Measurement and Automation Explorer, I could not change the wire mode. The whole section was greyed out. I put the card in a Windows XP machine running the newest Measurement and Automation Explorer and I could set the wire mode.
After uninstalling and installing the serial drivers and the card in the Windows 7 machine I still could not set the wire mode via Measurement and Automation Explorer or even programmatically. Through sheer dumb luck I looked at the com ports in the hardware manager and found an advanced configuration button. A window with a pull down menu allowed me to set the wire mode and it worked.
Is this the way 485 pci cards on a Windows 7 machine work now? I am posting this because I had a heck of a time finding the setting and hopefully someone will be spared some frustration in the future.