The online system differs from the less expensive line interactive UPS system as this system provides the highest quality power protection. This is done via double power conversion technique. The online UPS takes incoming power, converts it to DC voltage, conditions it, and converts it back to AC voltage.This means the UPS is Online since there is no delay to switch to battery. Use an online UPS for your critical applications, high availability servers, etc..The output of these online UPS systems are TRUE sine wave, better than the power from the electric company.