PURPOSE: To eliminate unrequired transfer start waiting time and to efficiently transfer information by dynamically controlling transfer starting time corresponding to the length of the write interruption time of a transmission buffer.

CONSTITUTION: When the information to be transferred is written in a memory 13 as the transmission buffer, the information is encoded 15 and transferred successively from the information for which writing is completed. At this time, a detector 17 detects a write state to the memory 13 and when it is detected that the information to be transmitted is not yet written in the memory 13, encodes specific signals to be transmitted to a transfer path L. The information sent through the transfer path L is received and when the information is predefined prescribed information, a write controller 27 suppresses the writing to the memory 23 as a reception buffer.