UPS serial port communication

[Jack Sprat]

I hope this group is somewhat appropriate. I didn't find a better group
for this question.

We just got an APC UPS (Smart-UPS 1000VA unit) to power a computer
system, one that their supplied software doesn't support. I'd like for
the UPS to tell the computer, at minimum, it lost power, and is about to
shut down, so the computer itself can go through the shutdown procedure.
I found the protocol to communicate with the thing over a serial port,
however I can't seem to get the serial port itself to work.
Supposedly it works at 2400 bps, 8 bit no parity, and several different
websites seem to confirm that. Yet it won't talk to me. I have no
problem writing software to talk to it, but it has to speak to me first!
It came with a serial cable which the websites say you have to use,
and I am using it. The UPS end is nonstandard (it has a 10 pin version
of an Ethernet RJ45 plug)

APC isn't helpful. They seem to want to keep how to talk to the thing a
secret and the person I talked to didn't seem to happy that I already
had the protocol and just needed to talk to the serial port.

 

[Nick]

IIRC you need to turn off any flow control (at least, you do in
hyperterm). It always seemed a bit hit-and-miss whether they were going
to talk or not.

I used to have a cable with a female DB9 and an RJ45 but I was never
sure what it was used for.

Most likely for configuring Cisco routers - if it reversed pins 1 to 8
it definitely was.