| 摘要 |
PURPOSE:To eliminate the need for a synchronizing signal by providing one of transmitting units with a condition monitoring circuit for a signal line and a circuit which stops transmission by the output of said circuit in a signal multiplex transmission system among transmitting and receiving units which share the signal line. CONSTITUTION:In a system which performs the time-division multiplex transmission of signals while transmitting and receiving units for a vehicle shares a communication line 15, at least one transmitting unit 16 is provided with a signal line monitoring circuit 19 and a transmission stopping circuit 20. Through the operation of the switchboard 17 of the transmitting unit, a signal generating circuit 18 generates a PCM signal which is inputted to the monitoring circuit 19. The circuit 19 monitors the condition of the signal line 15 all the time and then generates a signal for stopping the operation of the transmission stopping circuit 20 a certain time after any signal from the signal line is not detected, thereby sending a PCM signal from the circuit 18 to the signal line 15 by a transmitting circuit 21. Further, the signal from the circuit 21 and the signal from the signal line 15 are compared mutually by an interference detecting circuit 22 and when the both are not coincident, the circuit 20 is operated to stop the transmission of the circuit 21. |
