... including line interactive design, AVR (auto voltage regulations), USB communication port, alarms for battery backup, low battery and overload, ... free,Lead-Acid. Quantity20 pcsBack-Up Time (Full Load)7 min5 minRecharge Time 8 hrs to 90% of capacity ... continuously.Acoustic noiseAt 1 meter distance< 55 DBACommunicationsDB-9 Port RS232 serial interfaceIntelligent slotOptions,Web Power,AS400 or Win ...