A network attached storage (NAS) device includes a control unit, a wireless communication unit, a switch unit, a voltage conversion circuit, a battery unit, and a storage unit. When the wireless communication unit receives a request to access the storage unit, the wireless communication unit outputs a first control signal to activate the switch unit, the battery unit powers the voltage conversion circuit through the switch unit, and the voltage conversion circuit supplies power to the control unit and the storage unit. Until the wireless communication unit receives the request, the wireless communication unit outputs a second control signal to deactivate the switch unit, the battery unit cannot power the voltage conversion circuit through the switch unit, and the voltage conversion circuit does not supply power the control unit and the storage unit.

网络存储器(Network Attached Storage，简称NAS)中的存储单元在没有进行数据的读写操作时依然消耗电能，从而造成了电能的浪费。本发明提供一种能节省电能的网络存储器及应用上述网络存储器的无线通讯系统。