Howto silence APC UPS alarm sound that's attached to Synology
I'm using an APC Back-UPS ES 700G at home to keep my NAS and NUC running and do a safe shutdown in case of power failure. It's attached with an USB cable to my Synology NAS running DSM 7.x so the NAS can check the status of the UPS and act on it.
Unfortunately the battery of the UPS failed, causing it to make a loud alarm sound which can't be silenced on the UPS itself with a button. Here's how it can be silenced from the NAS.