Protection against powers spikes traveling through data lines ensures complete protection of your equipment from surges. It is very important to protect your equipment from "back door" surges traveling through data lines, as they can be as damaging to your equipment as surges traveling over power lines. Most other surge suppressors continue to let power through even after their circuits have been damaged, leaving your equipment exposed to future surges. APC's Surge Protectors fail safe, which means that once the circuit of an APC Surge Protector has been compromised the unit disconnects equipment from the power supply ensuring that no damaging surges reach your equipment.