Okay, cool, so I got an APC UPS to provide battery backup to my home network equipment. It has an RJ45 port, so it’s Ethernet and we’re good, right? Not so fast. That is nothing more than an RJ45 port that provides a collection of custom pinout circuits. You can connect either a USB or a serial cable to that port, and the USB cable is included in the box. So, no plugging this UPS box directly into your network for remote status information, it’s got to go through another computer first.
Okay, well how do I get it set up with GNU/Linux? The good news is
that this is actually rather quite easy. Just install and configure
apcupsd to connect with USB devices, and you’re all set to get
status information by issuing apcaccess status.
Please note that unfortunately, some of the newer UPS’s went through a stint with a proprietary Microlink protocol. For a short time, that was the only protocol that was supported, but a firmware upgrade was released to have fallback compatibility with the existing open protocols. Purportedly an open specification on the protocol would be published, but that looks to have never happened.
On the other hand, the good news is that the newer UPS’s support
Modbus over USB, which gives more detailed information than the basic
USB protocol. For a while, apcupsd only supported over Modbus over
serial, but I’ll have to check back for more details on the latest
versions.
In my particular case, I’m using a Raspberry Pi as a home server nearby, so the USB wiring is no issue at all, the software works on Raspberry Pi, and is available in the Raspbian repositories. This makes it real easy to get the status of the UPS over the network. Hooray!
20200120/DuckDuckGo linux apc ups serial protocol
20200120/https://forums.apc.com/spaces/7/ups-management-devices-powerchute-software/forums/general/9870/managing-smart-ups-x-1500-with-linux
20200120/DuckDuckGo apc Microlink protocol in Apcupsd
20200120/https://forums.apc.com/spaces/5/smart-ups-symmetra-lx-rm/forums/general/5993/microlink-protocol-in-apcupsd
Getting apcupsd up and running on Debian-based systems is pretty
simple.
sudo apt-get install apcupsd apcupsd-doc apcupsd-cgi
sed -i -e '/^UPSCABLE/c\UPSCABLE usb' \
-e '/^UPSTYPE/c\UPSTYPE usb' \
-e 's/^DEVICE/# DEVICE/g' \
/etc/apcupsd/apcupsd.conf
sed -i -e 's/ISCONFIGURED=no/ISCONFIGURED=yes/g' \
/etc/default/apcupsd
20200120/http://www.apcupsd.org/
20200120/http://www.apcupsd.org/manual/manual.html#quick-start-for-beginners
20200120/http://www.apcupsd.org/manual/manual.html#choosing-a-configuration-type
20200120/http://www.apcupsd.org/manual/manual.html#monitoring-and-tuning-your-ups
20200120/http://www.apcupsd.org/manual/manual.html#testing-apcupsd