A 1 phase true online UPS (uninterruptible power supply) is a type of power protection system designed to provide clean, continuous power to critical equipment in the event of a power outage or other electrical disturbance. The term true online refers to the fact that the UPS constantly converts incoming AC power to DC power and then back to AC power before supplying it to the connected equipment. 1 phase true online UPS ensures that the equipment receives a clean, stable power supply with no interruptions.