PURPOSE: To avoid erroneous setting of a frame pattern by providing a frame pattern generating section receiving mount location information of a sub- multiplex circuit from a frame pattern information section provided in a frame and generating a prescribed frame pattern corresponding to the information to the sub-multiplex circuit.

CONSTITUTION: A sub-multiplex circuit 2 is fitted to a frame 3. Thus, a prescribed frame pattern is generated corresponding to frame pattern information inputted from a frame pattern information section 4 provided in the frame 3. Thus, a same frame pattern is always generated from the sub-multiplex circuit 2 fitting to a same location as the frame 3. thus, error in the frame pattern setting is avoided and the transmission of the signal without error is attained.