BTW, I've noticed that all of these USB to serial drivers used by the Z-Wave controllers (all of which are based on the FTDI chips I guess), have their problems. If you do the wrong thing, they can lock up and never return despite the fact that the serial I/O call was made with a timeout. I don't know if that's the FTDI driver itself, or the controller that's not returning. But I've locked them up fairly often during development. The only way out is to unplug it and plug it back in. And I verified in the debugger that it was stuck in a serial port call that should not have blocked because a timeout was provided.