| 摘要 |
PURPOSE:To realize an accurate transmission of data, by exchanging a message for check of transmission system between two data devices and then comparing the same data at the transmitter or receiver side. CONSTITUTION:An on-line data is transmitted between data devicesIand II containing a microcomputer 1, an acoustic coupler 3 and a telephone set 4 respectively via a telephone circuit network 5. In this case, a transmission checking message is previously transmitted from the transmitter side to the receiver side and vice versa. After this, an item of the data is transmitted from the transmitter side, and the receiver side receives this item and at the same time send the contents of reception back to the transmitter side. The transmitter side compares its own contents of transmission with the sent-back contents from the receiver side to transmit the next data only when an agreement is obtained of the comparison. Otherwise an item of the data is transmitted twice from the transmitter side, and the contents of reception are compared at the receiver side. The receiver side transmits a retransmission request when no coincidence is obtained through the comparison and receives continuously when a coincidence is obtained respectively. |
