AEG Protect NAS Operating Informations page 81

VI Output Voltage Independent from mains supply
The UPS output is dependent on mains frequency
fluctuations; however, the mains voltage is processed
by electronic/passive voltage regulators. Previously
called: LINE-INTERACTIVE
VFI Output Voltage and Frequency Independent from
mains supply. The UPS output is not dependent on
mains voltage and frequency fluctuations. Previously
called: ONLINE
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