Valeri Galtsev galtsev at
Thu Nov 5 16:15:44 UTC 2015

On Thu, November 5, 2015 9:40 am, krad wrote:
> from what i remember the usb just presents itself as serial over usb, so
> that makes sense. THe network bit is a bit misleading as I think it means
> it talks to another apcupsd on a different host connected to a ups via
> serial, rather than direct to a network enabled UPS.

Network part means that apcupsd daemon on the machine (behind the same
UPS, but not connected to UPS with serial or USB cable) can talk to
apcupsd daemon on the machine connected to UPS with cable (serial or USB)
- this only kicks in when directly connected daemon says UPS has only 3
min of juice in battery left: starting clean shutdown on the machine. Then
other daemons connected to this daemon over network will start clean
shutdown of their respective hosts. If power returns "master" apcupsd will
try to abort shutdown if it didn't goo to deep into sequence, and "slave"
daemons will try to do the same. This is a bit simplified, as most likely
"master" passed all status data read from UPS to "slaves", and they make
their own independent decisions based on data and their setting (which may
be somewhat different).

This is as far as I recollect what I read some 10 years ago.


> On 5 November 2015 at 15:23, Robert Huff <roberthuff at> wrote:
>> Rob Byrnes <rbyrnes at> writes
>> >   You'll need a third-party tool to talk to it - sysutils/apcupsd
>> >   from ports works well on serial-connected UPS'.
>>         ... and USB-connected <waves> and - so I'm told -
>> network-connected.
>>         Respectfully,
>>                 Robert Huff
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Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247

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