The AC voltage sensor is used to indicate the presence or absence of an input mains supply or generator supply voltage can be used to indicate of a UPS system is running on battery power or an input AC supply. The AC Voltage Sensor indicates an ALARM/NORMAL condition in software and also via an LED mounted on the sensor. The sensor is designed for use worldwide. An SNMP interface can provide alarm/normal status information with SNMP traps sent when critical conditions occur. SNMP polling via ‘get’ is available to retrieve existing status and configuration parameters. A web browser interface is also available to display status and configuration parameters. When an alarm condition is activated the description and location of the fault can be sent via email, page or SNMP traps.