| 摘要 |
PURPOSE:To prevent errors of transmission control procedure by giving up a response urging signal received after multiplexing of an information message signal and a response signal are finished before a prescribed time is elapsed in a multiplex line concentrator to avoid multiplexing. CONSTITUTION:When a polling sequence 12 is outputted from a center side 1, an information message (1)13 is outputted from a terminal device 11, reaches the center 1 and an affirmative response 14 is returned. If no response 14 is returned at a time tau1 after the message (1)13 is transmitted, the device 11 transmits a response urging 24. On the other hand, the multiplexing of the message (1)13 is finished in the multiplex line concentrator 7, then the concentrator 7 receives the information message and response within a time tau2, multiplexing is conducted and when the message is response urging, an inhibition circuit gives up the response urging. Thus, if the message (2)15 is in error on a transmission line, a negative response 16 is returned from the center 1 and the message (2)17 is retransmitted. |
