COM1 problems

[Ian Smith]

On Sun, 3 Jun 2007 01:01:38 -0700 (PDT) Tim Judd <tjudd2k at yahoo.com> wrote:

 > Hi there, new installation, 6.2-STABLE.
 > 
 > I have a Belkin UPS on COM1 and sysutils/nut is trying to talk with it.
 >  I know it talks with it, because it has in the past.  The problem I'm
 > getting is that NUT is just filling the screen with errors, tty
 > overflows, and various problems related to communication on that port
 > with the UPS.

If this goes unresolved, try pasting some real error messages?

 > Looking at NUT's website, they say the UPS communicates at 2400 baud
 > 8N1 and I'd like to believe that.  I tested without specifying a speed:
 > # tip com1
 > and didn't get anything..  waited 30 seconds or so.  After reading
 > NUT's website, I tried:
 > # tip -2400 com1
 > and got binary data (not readable information, but data none-the-less).

Quite likely symptomatic of baudrate mismatch then (without seeing any..)

 > The kernel reports the port as sio0, but sio0 doesn't exist in /dev
 > the only serial port I see is cuad0{,.init,.lock} and that seems to be
 > hard-coded by some init script (but I don't know where).  cuad* also is
 > said to be a dialout line, not a generic com device.  /etc/remote does
 > indicate it is a generic device in the sense it will just pass
 > input/output...

You want cuaa0, which will likely appear when you open it.  cuad0 (once
ttyd0) might appear if you've got some getty running on it .. make sure
/etc/ttys has this set to 'off' - unless of course nut claims it there? 

tip or anything should be able to open cuaa0 anyway, assuming nothing's
actually locking (ie also using) that dialup (not 'dialout') device.

 > How can I configure /dev/cuad0 to be 2400 baud fixed?

'tip -2400 com1' will use /dev/cuaa0 at 2400, but I suspect that's not
the baudrate your UPS is talking.  Perhaps 2400 is only a default, and
your UPS is set to something else?  From within tip:
  ~?           help
  ~v           show variables
  ~s ba?       show baudrate
  ~s ba=1200   set baudrate .. till traffic looks like ascii ..

 > thanks for any tips and pointers....it's been a while since I've dealt
 > with serial ports.

I don't know your UPS (nor which model) but a little googling is a
dangerous thing; from 'nut belkin upd freebsd' this smelled useful:

 http://www.networkupstools.org/doc/2.0.1/INSTALL.html

Um, does it use a regular or cross-over cable?  CTS/RTS used?  Carrier
asserted, or needs setting up as a hardwired line? (as in /etc/remote) 

As Roland said:

 >> Look at sio(8), under FILES; the callin ports at /dev/ttyd?.

and maybe the para before FILES too.  Don't worry about the locking
stuff, though if curious, 'serial' has moved from /etc/ to /etc/rc.d/
but I've not played with that since FreeBSD 2.2.6 dialups years ago.

Cheers, Ian