i've had that happen before, sometimes the inital power draw of the unit is high, will cause my opus 150 to restart, I just make sure not to plug the XMD in while the psu is running.
I too made a cable following the instructions on this sight and have the same problem.
If the PC is powered up and I go to plug in the serial cable the PC will reboot. It reboots just fine. I don't think it is working though because it doesn't find a serial mouse of any device connected to the serial port.
I double and triple checked the wiring and all seems fine. Don't know why it reboots like that.
Is Pin 3 and Pin 8 on the mini din connector supposed to be connected when the cable is plugged in?
When the cable is totally unplugged there is no continuity through these pins. When I connected both the power cord and the serial connector in the MB then the two pins have continuity. The PC is off when doing this.
****It's working. It just doesn't like to be plugged in while the PC is running.