A wireless communication device sets a digital link on a wireless channel between a master device and a slave device, compresses a sound signal in an ADPCM scheme, and carries the sound signal in a sound packet to perform communication. In a master device, a PCM signal is converted into ADPCM data by an ADPCM encoding unit. Next, the least significant bit of n-bits is set according to the number of “1” of the n-bits of the ADPCM data by a transmission conversion table. In a slave device, it is determined whether error has occurred according to the number of “1” of the n-bit data in received data. If error exists, the n-bit sound data is converted into mute data through a reception conversion table. The sound data converted through the reception conversion table is converted into a PCM signal from an ADPCM format by an ADPCM decoding unit.