Notes on connecting a Best Fortress UPS to a NeXT serial port:

Hardware:
  The correct cable wiring is as follows:
      UPS (DB-9 male)      NeXT (Mini DIN-8 male)
      ---------------      ----------------------
           1                      3
           2                      5
           4                      4

Software for graceful shutdown:
  The CheckUPS for Unix software package from Best includes a BSD Unix
  version called checkups.bsd.  I got the floppy disk version of this
  software; the 3.5 inch DOS-format floppy that comes in this package
  reads fine on the NeXT.  To compile the file, you not only have to
  rename it to checkups.c, but also change carriage-return line-feed
  endings to just line-feed (i.e. newline).  Here's how I got the
  program off the disk, changed the line ending convention and name,
  and compiled it:
    tr -d '\015' < /DOS/checkups.bsd > checkups.c
    cc -s -O -o checkups checkups.c               
  This compiles with two ignorable warnings. Note: if you were to do
  the obvious thing and add the -bsd flag to cc, the warnings would go
  away, but the program wouldn't always work right, because toupper
  and tolower are used on arbitrary characters.  There is also a
  latent bug that doesn't seem to strike on the NeXT; see the end of
  this file if you care.  Other than these caveats, as far as I can
  tell from looking at it, checkups it should run fine in its as-is
  state.  However, I have only actually tested it after making two
  minor modifications:
    1) I changed it to directly run "/usr/etc/halt -p" to shut the
       system down rather than an /etc/upsdown script that would
       presumably contain this line.  This is a matter of taste and
       I'm not convinced I'd recommend it.
    2) I changed the printmsg function to use syslog (at the emergency
       priority level) rather than the wall command to display the
       messages.  The normal /etc/syslog.conf configuration is set up
       so that emergency messages are in fact broadcast to all
       logged-in users, just like with wall.  However, additionally
       the messages wind up on the console and in the log file
       (/usr/adm/messages).  This is useful in our situation, since
       there is typically no one logged in to the file server
       (particularly when the power is out, since nothing they could
       log in from is on an UPS), so the broadcasting would likely
       never be seen, but it is nice to have a record in the log file
       of what happened.

Security:
  If you don't make the protection modes on /dev/ttya more restrictive,
  then any normal user, even logging in remotely, will be able to
  power your machine down by just sending the right string to that
  serial port.  So, I'd recommend making that device accesable only to
  root.  In fact, I'd go further and do the same for all the various
  flow controlled and dial in/out variations on tty, i.e.
  /dev/{tty{d,},cu}{f,}a

Latent bug:
  sendstr doesn't return anything at all, but msgrdy checks whether it
  returned ERROR (i.e. -1).  This works on the NeXT because something
  other than -1 happens to have been left in the relevant register.
  To fix this for real, just remove the check.

Please let me know if you have any additional information (or
corrections, heaven forbid) you would like to contribute to this file.
  -Max Hailperin <max@nic.gac.edu>, Gustavus Adolphus College