PSi1000VAT#48VK series are applicable to telecom systems with 48VDC power supply, adopting high efficiency SPWM inversion technology. PSi1000VAT#48VK series can be connected to teleprinter, telegraph terminal, wire-less paging equipment, data switching exchange, local exchange, microwave communication equipment, program controlled exchange charging system, fax machine and all kinds of AC instrument, computer equip-ment and various communication equipment. Meanwhile, PSi1000VAT#48VK Series can be used for air condi-tioner.