A backboard is disclosed according to the embodiments of the present invention. Sockets for connecting at least two sub-racks are respectively disposed at two sides of the backboard, and the sockets include first sockets for splicing a first type of sub-cards and second sockets for splicing a second type of sub-cards. Connectors, the number of which is not smaller than that of the second sockets, are disposed at the first sockets, and connectors, the number of which is not smaller than that of the first sockets, are disposed at the second sockets. One of the connectors at the first sockets is connected to one of the connectors at each of the second sockets, and one of the connectors at the second sockets is connected to one of the connectors at each of the first sockets.