| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to continue transmission without interruption even when abnormality occurs in one of cluplexed transmission lines by providing the system with a transmission line switching means for opening the transmission line generating abnormality at the time of detecting the occurrence of the abnormality in the transmission line and executing transmission/reception by the use of the remaining normal transmission line. SOLUTION: Respective TCP protocols 31, 32 previously set up connections so as to always transmit data on duplexed transmission lines BA, BB. In transmitting processing, the same data are transmitted from a transmitting side to both the transmission lines BA, BB. In receiving processing, a receiving side informs a duplexed processing user of data in accordance with arrival priority. When abnormality occurs in one transmission line BA or BB in half- duplex disconnection processing of the connections, the connection of the abnormal system is opened (interrupted) and only the remaining normal, transmission line BB or BA is used for transmission/reception. |
