Abstract: Disclosed is a device for storing and retrieving log files and testing circuits that includes a Control and Management Module, a Network Interface Module and a Serial Interface Module. The Network Interface Module connects with an SFP interface of data transport network to supply power and achieve a network connection. The Serial Interface Module connects to a serial port of equipment to store the output logs into the device. Remote management equipment can access the inventive device via telnet or other means. The device can be conveniently carried and installed and can work automatically after power up, which avoids taking additional power from the equipment room and saves on installation space.