... WaveformTrue Sine WaveHarmonics Distortion<3% (Linear Load,Full Load)/<5%(Non-linear Load) Crest Factor3:1Power Factor0. ... DischargeBeeping sound every 4 seconds after utility power failsBeeping sound every second if battery approaches ... IndicatorsLCDVFD/LCD Indicator StatusInput/Output Voltage,Frequency,Output Power,Battery,Utility,Inverter,Overload,Fault,BypassCommunication PortRs232/ ...