> 
> I try to do serial console, but can not restart mac.
> Allen say Quadra900/950 has different chip for serial port,
> so maybe this couse problem.

You might try putting the serial ports in "compatability"
mode under MacOS. It's a long shot, but it might work (I think
there's a "Serial" Control panel, maybe "Serial Ports" or
something).

If there's no way to put it in compatability mode, then
just ignore my suggestion. :-) I've never used one of these
computers, and am just going on knowledge from looking at our
PowerMacs.

Take care,

Bill