| 摘要 |
PURPOSE:To attain the ER control of a called terminal equipment without manual intervention or complicated controller by allowing an automatic ER (terminal equipment ready signal) control circuit 5 provided to a MODEM at the called party to detect the stop of a carrier of a caller side so as to turn off the signal ER simulatingly. CONSTITUTION:When an incoming call from an exchange 4 is detected with a called side terminal equipment 1 in the ready state, i.e., with a signal ER set to logical 1, a level of a terminal CI is logical 1, then a signal ER' outputted to a called side MODEM 2 is logical 1 and the communication is applied usually. When the communication is finished and the carrier from the caller side is stopped, a detection signal CD inputted from the MODEM 2 is logical 0, an output of a flip-flop 15 is inverted and the signal ER' is logical 0. Thus, the MODEM 2 recognizes that the terminal equipment 1 is turned off and a line connection command CML is turned off, then a reply automating network controller 3 disconnects the terminal equipment 1 from the line. Further, inverters 12 are provided in multi-stage, because the delay time is given to match the timing.
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