Power spikes over telephone lines are more common than electrical power surges. To use this feature, plug the telephone cable connected to your modem into the output port of the surge protector. Then, plug the surge protector into the wall outlet. With that simple step, you'll save yourself hundreds of dollars in repairs and replacements. One lightning strike can cost you thousands of dollars if you don't have surge protectors in place.
Surge protectors protect against power spikes, but are of little help when the power goes out.
Disk crashes usually occur because of a sudden loss of power. You can also lose hours or days of work, because you didn't save your work before the power loss. A UPS keeps power going for a short period of time so you can save your work and shut down the system gently. Some uninterruptible power systems also have a serial cable, which plugs into your computer and tells the computer to shut itself down at the loss of power. This feature is handy for situations where you leave the computer on for long periods, unattended.