The equipment is normally powered by mains power and the UPS only takes over in case of a cut or too much reduction of the mains voltage.
Off Line technology keeps the devices it protects energized for enough time to back up its data and/or turn off devices properly.
This switching to batteries takes some time (switching time in general >4ms) which will not be an issue for computers with switch mode power supplies, but this may be a problem for more sensitive equipment (measurement instruments).
Off Line UPS are the most economical. They are recommended for single-post computers (PC type) dedicated to office and small servers in a low-disturbed electrical environment such as an agglomeration.
The Z3 ZenBox EX series of UPSs have been designed to provide your PCs and digital entertainment equipment with protection suitable for a home configuration against power problems and electrical disturbances. Its modern and compact design allows it to integrate elegantly into your private multimedia space. Learn More