| 摘要 |
PURPOSE:To shorten a signal stop period for calling a telephone set, and to eliminate the unnaturalness of a call signal being sent out, by sending out a synchronizing signal preceding to a stop signal. CONSTITUTION:A call signal generator SIG is provided with a call signal stopping control circuit PCTL' and a synchronizing signal sending circuit SOSC, and the operation time extent and synchronizing signal for a call signal transmission changeover switch rg is sent out of the circuit SOSC precedently to the stop of a signal due to the switching of a contact P. The synchronizing signal from this circuit SOSC is inputted to respective control parts CTL1-CTLn to shorten the signal stop periods of subscriber circuits LC1-LCn for calling telephone sets sub1-SUBn. To send out call signals, differing in transmission/ stop period by a synchronism control system, the stop period of the call signals being sent out is shortened, thereby eliminating the unnaturalness of the call signals. |
