I'll keep an eye on this thread, since I'm seeing a similar situation. I'm also using an FTDI chip and communicating with it via a USB-to-serial converter under Windows 7. I made a small program that looks for the COM port the USB device is claiming, sends out a quick VISA write and if it sees the response with a VISA read it knows the USB port on the device is good. It worked fine for about a week or so, but now all of a sudden I'm finding when I plug in the USB cable the "USB to serial" driver will pop up, as it should, but Windows will claim the device is a USB mouse and the cursor will go nuts and the device won't communicate anymore.
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Amateur programmer for over 10 years!
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