What are the functions of UPS?

What are the functions of UPS?

1.Absorb relatively small power surges.
2.Smooth out noisy power sources.
3.Continue to provide power to equipment during line sags.
4.Provide power for some time after a blackout has occurred.

In addition, some UPS systems or UPS/software combination provide the following functions:
1.Automatic shutdown of equipment during long power outages.
2.Monitoring and logging of the status of the power supply.
3.Display the Voltage/Current draw of the equipment.
4.Restart equipment after a long power outage.
5.Display the voltage currently on the line.
6.Provide alarms on certain error conditions.
7.Provide short circuit protection.