The power goes out in Costa Rica every once in a while, so I bought a small UPS, just for the modem, so that internet access would not be disrupted during short outages. It so happens that the UPS is from Tripp Lite.
It turns out, whenever the power goes out, the UPS announces this fact by beeping. In a very loud, annoying, high pitch. Over and over again. Every several seconds. Three times in a row, and then again.
So I bought a UPS so I could continue working when there isn't power. But then, when the power goes out, I can't work because the UPS becomes so distractingly loud.
It doesn't matter if it's day or night, either. If the power goes out while I'm sleeping, I don't really care. But the UPS will make absolutely sure to wake me up!
There does not appear to be any button to disable this horrid beeping. The only cure I've found is to turn the unit off. At which point, it's as good as having no UPS.