PURPOSE: To constitute an accurate interlocking system by eliminating error of clocks contained in respective devices when synchronization of each device is conducted using clocks contained in each device in an interlocking system and the like consisting of a plurality of devices such as video and audio systems.

CONSTITUTION: The time data of the clock contained in a master VTR 1 is transmitted to each slave VTR 2 by way of a remote control transmission cable 3 and the clocks contained in respective VTR are synchronized using a second synchronization signal cable 4.