Suppose computer is connected to UPS and UPS is connected to the computer with USB cable. Some software runs on the computer, which is capable to shut it down gracefully on power loss.
Suppose power loss happened. UPS sent a command to the software to shut down, an the computer did it.
Now suppose power supply has returned before charge depleted. So power wasn't loss at computer's end.
How computer can know about it and turn on?
Best Answer
Most ordinary UPS units do not turn a computer back on. Mostly what I see is that it is the computer UPS control software that shuts down the machine.
If you are present, just turn it on. This is what I do. Very simple.
If you are not present, try Wake on LAN and start it remotely that way.
I use the middle method because someone is often around to turn on the computer(s).