Movin’ on UPS
Much as surge protectors come in at many price points and offer many different levels of protection, Uninterruptible Power Supplies go from pretty cheap ($50) to a few hundred dollars for a small office to many thousands for organizations that invest heavily in IT equipment and have critical information on it. We'll look at how to choose a UPS for a home computer or SOHO set up.
UPSs include surge protection, but it is a good idea to have at least a simple surge protector in front of them, it is extra protection for your equipment and for the UPS; depending on what you spent on the UPS, you may even want a rather nice surge protector guarding it.
There are two general kinds of UPS available to the home or small office user: standby or online. A standby system can be thought of as a surge protector and noise filter beside a battery. It provides power to the connected equipment from the wall until the power goes out, at which point power comes from the battery. An online or line-interactive system can be thought of as a surge protector in front of a battery. Incoming power charges the battery, and power is drawn from the battery to the equipment. If the power goes out, the battery powers attached components, but can’t charge and eventually runs down.
Either system allows your equipment to run briefly during a power outage, potentially avoiding a botched firmware upgrade and other forms of data loss or equipment damage. Line-interactive models, however, also offer better potential in terms of power conditioning and voltage regulation since the connected equipment is always drawing from the battery. These UPSs are also more expensive, only available on units over $100.