PURPOSE: To decrease the number of wirings required to transfer parallel signals among respective packages in a device and to easily change the wirings.

CONSTITUTION: In synchronism with a synchronous signal 5 and a clock signal 6 in the device, the parallel signals sent out of the respective packages 1A, 1B, and 1C are converted by interface circuits 2A, 2B, and 2C into serial signals; and the signals to be connected by the individual packages among all the converted serial signals are registered in the memories 13 of the respective interface circuits 2A, 2B, and 2C, the signals to be connected are latched from all the converted serial signals, and then serial/parallel conversion is performed again to secure connections among the packages.