DATA TRANSMISSION SYSTEM

PROBLEM TO BE SOLVED: To provide a data transmission system capable of exchanging bytes between data groups for avoiding system down caused by disability in error correction based on an error-correcting code(ECC). SOLUTION: In a data transmitter 1, transmitting data 10 are divided into two data groups and ECC are added to the respective data groups. When any error is detected by error detecting/correcting circuits 21 and 22 in a data receiver 2 and this error can be corrected, the error is corrected. When a 2-byte error occurs, an exchange byte determining circuit 26 determines a byte, with which no error occurs, out of the other data group and exchanges a byte, for which the occurrence frequency of error is high, with this determined byte so that the bytes having the high occurrence frequency of error can be distributed.