Actually I was wondering if it would be possible to hook a resistor or such in parallell with the 12 volt line, except there would be a transistor in there so the voltage could be controlled via the GPO. Except that's a moot point because of what Henry said about the PWM signal.

Sweet, looks the it'll fit. Once I get a bit of cash flow I'm definatly going to get me one of those.

linear - Would it be possible to create a circuit using a lead from my power supply and a transister hooked to the GPO so that it would only use 1 GPO per fan?

Both - Thanks for the info, I'd still like to know the thickness. It says in the manual, but the picture is too small for me to make out ...

First, with the cable plugged in, how thick is the unit from front to back?

Second, is it possible to lower the GPO output to 7 or so volts via software? I'd really like to use this to replace my baybus, and simple on/off action is too basic for my liking.