>Hello,
>
>I have a PowerComputing PowerCenter 132 machine and I've been trying
>desperately to get in to Open Firmware. On this machine, the default
>input/output devices is set to 'ttya'.

I'm working with the same model of box --- there's been one around here
for just about a month now.  Serial Console is the only way to work with
setting it up.

>I've tried to use BootVariables 1.3 and it doesn't seem to be able to
>write changes to the PRAM. 

The local PowerCenter moved in with no MacOS; I know nothing of
BootVariables.

>I've also tried to use a serial cable (Mac-to-PC) and get into it with a
>machine running DOS using DOSTunix (a free terminal emulator) with the
>serial comm drivers loaded. I'm not sure if I am doing it right. I set the
>baud rate to 38400 with 8N1 and then open the serial port on the PC. I then
>switch the PowerCenter ON and hold down Cmd-Opt-O-F and wait for the prompt
>to show up, but it doesn't. Am I doing something wrong?

I've got an ancient-of-days-Amiga nearby set up to be a console.  The
working setup I've got is:
* Generic Null-Modem cable between the PowerCenter and the Amiga.
* VLT (vt100 emulator) running with:
  * 38400 bps
  * 8N1
  * No DSR
  * Handshaking set to NONE

I found that between the two boxes here, trying to use DSR results in
constant warnings, while setting the Handshaking to anything other than
"NONE" blocked all output from the PowerCenter.  Given this, I'd say
that if the cabling is okay, check the Handshaking (and possibly DSR,
if your software supports it).

If you've got MacOS still loaded, you could check the serial connection
between the two boxes with something running on that.
--
T. M. Pederson
salvage@galaxy.plethora.net