This may be more of a driver than a hardware issue. I can't recommend this device for 64-bit Windows-7 applications. It's the first device that I've seen cause a blue screen in an otherwise solid Windows-7 machine.This device was also quite awkward in an otherwise straightforward Labview-based serial interface setup. (Was using Putty for testing at the time of the blue screen)Looking forward to trying something else... Until then, will revert to a Keyspan USA-19QW attached to an old WinXP box for testing...Cheers!