When it is detected that a CRC check is acceptable in Blind Transport Format Detection (BTFD) processing, the BTFD processing is halted from this moment onward, the number of bits of voice code of each class is decided based upon the bit rate of each class in a bit-rate combination that prevails when the CRC check is acceptable, the voice code of each class is demultiplexed from receive data based upon the number of bits and the demultiplexed voice code is input to a voice codec.