I could be wrong, but I've always assumed stop-A was an OpenFirmware function 
on Suns.  If that's true, is there any equivelant for the OF that Apple uses?  
In particular, my 7500/OF 1.0.5 system?  I managed to hang my system up the 
other day and had to just hit the power button to get it to reboot.  
Sometimes I work on it remotely over a terminal server and can't do that.  A 
key stroke to drop into OF would do it though.

BTW, the pin-out on the old serial ports is the same (or close enough) as was 
on the old SGI systems.  SGI used to ship their systems with a mini-DIN to 
DB-25 adapter.  This same adapter works on the Mac.  Just something to keep 
in mind if you're going through an old junk pile.

-Rich