APCSmart-UPS, 4000 Watts / 5000 VA,Input208V / Output208V, Interface Port DB-9 RS-232, SmartSlot, Rack Height 5U. Includes: CD with software, Rack Mounting support rails, Smart UPS signalling RS-232 cable, User Manual, Web/SNMP Management Card. SmartSlot - Customize UPS capabilities with management cards.Cold-start capable - Provides temporary battery power when the utility power is out.Serial 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.Resettable circuit breakers - Enables a quick recovery from overload events.Hot-swappable batteries - Ensures clean, uninterrupted power to protected equipment while batteries are being replacedDisconnected battery notification - Warns when a battery is not available to provide backup power.Automatic self-test - Periodic battery self-test ensures early detection of a battery that needs to be replaced.Adjustable voltage-transfer points - Maximizes useful battery life by widening the input voltage window or tightening the output voltage regulation.Adjustable voltage sensitivity - Provides the ability to adapt the UPS for optimal performance in specific power environments or generator applications.Audible alarms - Provides notification of changing utility power and UPS conditions.Serial Connectivity - Provides management of the UPS via a serial port.Temperature-compensated battery charging - Prolongs battery life by regulating the charge voltage according to battery temperature.Boost and Trim Automatic Voltage Regulation (AVR) - Gives higher application availability by correcting low and high voltage conditions without using the battery.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. UL, FCC, CE, C-Tick approvals.Rack/Tower convertible - Protects the initial investment in the UPS when migrating from tower to rack-mount environment.Network manageable - Provides remote management of the UPS over the network.Adjustable voltage sensitivity - Provides the ability to adapt the Power Conditioner for optimal performance in specific power environments or generator applications.LED status indicators - Quickly understand unit and power status with visual indicators.Boost and Trim Automatic Voltage Regulation (AVR) - Gives higher application availability by correcting low and high voltage conditions without using the battery.Intelligent battery management - Maximizes battery performance, life, and reliability through intelligent, precision charging.Power conditioning - Protects connected loads from surges, spikes, lightning, and other power disturbances.Temperature-compensated battery charging - Prolongs battery life by regulating the charge voltage according to battery temperature.Automatic restart of loads after UPS shutdown - Automatically starts up the connected equipment upon the return of utility power.Automatic self-test - Periodic battery self-test ensures early detection of a battery that needs to be replaced.