COMMUNICATION SYSTEM

PROBLEM TO BE SOLVED: To easily secure synchronization between a call origination part and a call termination part by controlling the speed of a prescribed processing in a repeater station based on a data amount measured by a processing standby data amount measurement means. SOLUTION: Once communication start signals have been received, a buffer storage amount measurement part 753 measures the storage amount of the voice data of a reception buffer 752 and sends it out to a clock frequency correction part 754. The clock frequency correction part 754 judges whether or not the storage amount of the voice data exceeds a prescribed value, and in the case of exceeding it, judges that the processing speed of an A/D conversion part provided in a transmission station is faster than the processing speed of a D/A conversion part 745 determined by the clock 746 of a call termination station and controls the clock 746 so as to raise a frequency. On the other hand, in the case of being less than the prescribed value, it is judged that the processing speed of the A/D conversion part is slower than the processing speed of the D/A conversion part 745 determined by the clock 746 of the call termination station and the clock 746 is controlled so as to lower the frequency.