Twin changing online design, adopting the DSP technology, tacking the UPS on perfect protection and high dependability. Agile online technology fits to kinds of laden systems. Stand-alone, online1+1, onlineN+1. The system has passed strictly short circuit test and 2kva high voltage insulated test. The isolation of the output transformer reducing the wave of the laden and the immediacy molestation of the city electricity. The DSP technology controlling the UPS speedy, exactitude, credibility and steady. Powerful intelligent supervise function, providing the RS232 port, dry port, battery testing port and online port.