When you own an Asustor NAS (or any other) there is a fair probability you have its storage media protected against damage caused by power failures using an Uninterruptible Power Supply.
Home Assistant features a nice way to get a hold of the UPS data for monitoring, and of course even more important, automation purposes, even if the UPS is only connected to the NAS by a USB cable.
In order to make use of this:
1 - Launch the webportal of the NAS and click on the app icon External Devices.
2 - If you have connected a UPS you will now see it in the overview. Click on it or go to UPS in the left list, either way is good.
3 - Click Preferences and make sure Enable network UPS Support is enabled, do not forget to click OK after.
4 - Check these values in the UPS overview, Network UPS type: Network UPS Server, Network USP Support: enable.
6 - Review the other settings that work best for you (or do this later).
7 - The NAS will now broadcast the data that the Network UPS Tools (NUT) integration likes so let’s add that into Home Assistant.
8 - A popup appears where you replace localhost with the IP address of your NAS, leave the port as is and do not fill in any user/password details.
9 - That should be it and the UPS can now be viewed and used, like adding an automation to shut down and save (eMMC/SSD/SD) memory and/or databases from getting damaged/corrupted.
10 - If you like you can set the scan interval by clicking Configure, by default it is set to 60 seconds.