The ASTHA offline UPS is a type of UPS that directly supplies the power to the AC load from the AC mains in normal operation and uses an inverter to power the AC load from the DC battery. Since there are two separate lines of supplies, the output supply must be switched between the two sources. Voltage and frequency dependent” UPS in compliance with IEC 62040-3, also referred to as offline, protects against many problems in your network. Under normal conditions it conducts the input current to its outlet. When the power supply fails it switches over to a built in battery to compensate for any variations in the mains supply.