| 摘要 |
PURPOSE:To reduce the amount of communication transmission, by transmitting the selected sequence in a specific timing for time sharing of each slave station when the transfer of the character sequence is absent, in the multidrop data communication system of contention system. CONSTITUTION:A plurality of slave stations 111, 112 are in branch connection to a control station 14 with transmission line 12 and reception line 13. Further, if the transfer of character sequence is interrupted for a given time or more on the reception line 13, a time sharing timing circuit 19 transmits the output of ''1'' in a given timing to one input terminal of an AND circuit 23 based on the output of an off-delay timer 17 in the slave stations 111, 112. On the other hand, the output of ''1'' is input to another input terminal of the circuit 23 of an AND circuit of the slave stations 111, 112, based on the data transfer request. Accordingly, the selective sequence is transmitted from a selective sequence generator 20 of the slave stations. Thus, the amount of communication transmission can be reduced. |
