[Nut-upsuser] APCsmart serial port problem

Patrick Nolan Patrick.Nolan at stanford.edu
Wed Jun 6 18:06:04 UTC 2007

Patrick Nolan wrote:
> Arjen de Korte wrote:
>> This looks more like a hardware/interrupt problem to me. Do you have the
>> chance to test this on a different port (or even machine) and checkout the
>> results?

I figured it out.  It's a pretty obscure software problem.  The file
/etc/inittab contains this line:
co:12345:respawn:/sbin/agetty ttyS0 9600 vt100-nav

That causes an unkillable  agetty process to run on the serial port,
setting it to 9600 baud.  Once I got rid of that, the communication
began to work as it should.  This line wasn't there in clones of
Red Hat Enterprise 4.  It seems to be a version 5 addition.

Now I'm trying out the manufacturer's software again to see if I can
live with it.

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