... class product. HT-HM series UPS be widely applied to the telecommunication, bank, stock exchange centre, transportation, ... input frequency50Hz±10%,60Hz±10%ChargeCharge modeconstant current to constant voltage, with temp compensationBatteryBattery Typemaintenance-free ... 100 meters’ rise. Altitude 4000m MAX)Communication InterfaceRS232, RS485; optional SNMP card(for internet long distance monitor )Noise ...