AEG Protect C.1000 Operating Instructions Manual page 60

60
VFD Output Voltage and Frequency Dependent from mains
supply. The UPS output depends of mains voltage
and frequency variations. Former notation: OFFLINE
VI Output Voltage Independent from mains supply
The UPS output is independent of mains voltage and
frequency variations. The mains voltage however is
rectified by electronic / passive voltage regulators.
Former notation: LINE-INTERACTIVE
VFI Output Voltage and Frequency Independent
from mains supply
The UPS output is independent of mains voltage and
frequency variations. Former notation: ONLINE