[comp.sys.dec] Using 19200 baud rate on DS 3100

rick@ut-emx.uucp (Rick Watson) (10/01/90)

Is is legal to select 19200 (EXTA) on the serial ports on a
DECStation 3100?  It seemed to work for me for awhile, now I
seem to get random speeds and the port hangs, requiring
a reboot to clear it.  9600 works fine.

Rick Watson 
The University of Texas Computation Center, 512/471-3241
   internet: rick@digate.cc.utexas.edu       bitnet: watson@utadnx
   uucp:     ...!cs.utexas.edu!ut-emx!rick   span:   utspan::utadnx::watson

grr@cbmvax.commodore.com (George Robbins) (10/02/90)

In article <37801@ut-emx.uucp> rick@ut-emx.uucp (Rick Watson) writes:
> Is is legal to select 19200 (EXTA) on the serial ports on a
> DECStation 3100?  It seemed to work for me for awhile, now I
> seem to get random speeds and the port hangs, requiring
> a reboot to clear it.  9600 works fine.

It's for sure that something doesn't like 19200 baud out there...

The man pages for pm(5) is somewhat obtuse.  It says that port #2, "can"
be a console port and the determination is made at power on.  It also
says the the console port must be set at 9600 baud.  It further says
that in multi-user mode if the console port is used, no other devices
can be attached.  Really confusing, eh?

Anybody want to take a whack at the following questions?

1) What actually control whether the port is used as a "console port"?
   If I leave a termina plugged in, or a modem does that become the
   console if the system crashes and reboots?

2) If the port is not being used as a "console port", then can one
   set the baud rate to one of the 16 arbitrary speeds?

3) Is 19200 baud, supposed to work, not supposed to work, broken somehow
   or locked out by the 9600 baud "requirement"?

4) If the port is being used as a "console port", does the really mean
   that I can't use port #3 as a local terminal/printer port?  Can I
   still use the keyboard/mouse on ports #0 and #1?

-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr@cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)

santiago@lerad.pa.dec.com (Eduardo Santiago) (10/03/90)

grr@cbmvax.commodore.com (George Robbins) writes:
>Anybody want to take a whack at the following questions?
>1) What actually control whether the port is used as a "console port"?
>   If I leave a termina plugged in, or a modem does that become the
>   console if the system crashes and reboots?
If you do not have a video SIMM (CFB/MFB), the console will default to
that serial port.  I believe this configuration is sold as a server.

>2) If the port is not being used as a "console port", then can one
>   set the baud rate to one of the 16 arbitrary speeds?
Yes, no problem.

>3) Is 19200 baud, supposed to work, not supposed to work, broken somehow
>   or locked out by the 9600 baud "requirement"?
19200 baud does not work on PMAX.  Sorry.

>4) If the port is being used as a "console port", does the really mean
>   that I can't use port #3 as a local terminal/printer port?  Can I
>   still use the keyboard/mouse on ports #0 and #1?
What the man page was probably trying to say was that if you are using
that port for your console, you may not disconnect the console terminal
and plug in a printer or modem or somesuch.  The rest of the serial ports
are unaffected, although you won't have much luck with keyboard/mouse
since you do not have a display device.

In short:  if you are using your PMAX as a workstation,  ignore all that
jazz about serial console.

And in reply to the original question:  PMAX hardware does not allow 19.2K.

Obligatory disclaimer:  I do not speak for Digital or for WSE.
Ed Santiago                                      santiago@decwrl.dec.com
DEC Workstations Systems Engineering             ..decwrl!santiago