US Patent 7304980 Method of transmitting transparent data

Transparent data transmission service is kept optimal in the quality provided. A transmission quality monitor section, provided in a base-band signal processing circuit of each apparatus, monitors an error in reception data and an response, to the data transmitted, of from an opposite apparatus, thereby measuring an error rate. When the error rate exceeds a set level, the transmission scheme as to transparent data is switched over to a scheme higher in probability of normal reception (e.g. packets added with error correction codes). Meanwhile, when the error rate lowers to a set level or lower, the transmission scheme as to transparent data is switched over to a scheme higher in transmission efficiency.