| 摘要 |
<p>A data communications system includes a transmitter (100-108) for transmitting messages, each of which include message characters, a verification portion and a message sequence number. The message sequence number for each message differs from the message preceding it. A receiver (110-122) includes means for verifying the accuracy of the received message and for returning to the transmitter a signal which is either an acknowledgement signal, if the message is inaccurately received, or an error signal, if the message is inaccurately received. To prevent the utilization by the receiver of redundantly received messages, which might occur if the acknowledgement signal is incorrectly received at the transmitter, the receiver includes means (118) for comparing the message sequence number with the message sequence number of the last accurately received message (116) and for storing (126) the message only if the message sequence numbers are different.</p> |
