Battery-protected and surge-only outlets Reserves power capacity and run time for connected equipment that require battery back-up while providing surge only protection for less critical equipmentSerial Connectivity Use any Home Automation network to monitor and control the S20 through its RS-232 serial port. For information on how to communicate with the S20, see APC's Application Note #102. Crestron and AMX installers should visit their respective websites for information on how to integrate the S20 into those networks.Automatic self-test Periodic battery self-test ensures early detection of a battery that needs to be replaced.Audible alarms Provides notification of changing utility power and UPS conditions.USB connectivity Provides management of the UPS via a USB port (not available on all models).Serial Connectivity Provides management of the UPS via a serial port.Intelligent battery management Maximizes battery performance, life, and reliability through intelligent, precision charging.Safety-agency approved Ensures the product has been tested and approved to work safely with the connected service provider equipment and within the specified environment.LED status indicators Quickly understand unit and power status with visual indicators.