Patent ID: 8321737

Claim:
A data transfer apparatus having a data transmission device for transmitting data and a data reception device for receiving via a transmission path data transmitted by a counterpart side data transfer apparatus other than the data transfer apparatus, the data transmission device comprising: a data generation unit for receiving an input of transmission target data and for generating transmission data that is the transmission target data with error testing information added; a data recording unit for recording the transmission data generated in the data generation unit; a data transmission unit for transmitting the transmission data generated by the data generation unit to the counterpart side data transfer apparatus; and a retransmission control unit for causing the data transmission unit to transmit the transmission data recorded by the data recording unit to the counterpart side data transfer apparatus when a retransmission request of the transmission data transmitted by the data transmission unit is received, and the data reception device comprising: a data reception unit for receiving the transmission data transmitted by the counterpart side data transfer apparatus as received data; an error testing unit for testing the received data by using the error testing information added to the received data and when an error occurs, for transmitting a retransmission request of the received data in which the error occurred to the counterpart side data transfer apparatus; an error data recording unit for recording error reception data having the error detected by the error testing unit; and a failure position identifying unit for comparing the transmission data recorded in the data recording unit with error reception data recorded in the error data recording unit and for identifying a failure position, wherein the failure position identifying unit taking exclusive OR of a transmission packet recorded in the data recording unit and an error packet recorded in the error data recording unit and identifies the failure position.