... Mode)/50±0.2%Hz(AC Frequency exceed 46~54Hz)50±0.2%Hz(Battery Mode)Output ... utility power failsBeeping sound every second if battery approaches final dischargeOverload ProtectionContinuous beepingFaultContinuous beepingPROTECTIONOverload ProtectionOverload ... Indicator StatusInput/Output Voltage,Frequency,Output Power,Battery,Utility,Inverter,Overload,Fault,BypassCommunication PortRs232/ ...