The socket with usb is actually equivalent to a power adapter installed in the ordinary socket, and the other is similar to the ordinary socket. When the socket is bought back, the input end of the usb power adapter should have been connected to the conductive part of the socket. If the stream connection is good, the input end of the power adapter should be connected to the firewire neutral line of the socket. Then the mains live line neutral line ground line respectively according to the sign a pair of sockets on the line.