| 摘要 |
<p>A signal sending control system for use in a telephone system which employs telephones having a bell for calling and an exchange employing a speech network composed of electronic switches. The signal sending control system includes a ringing signal sending circuit having a signal source for generating n continuous ringing signal and interrupting means for controlling sending of the ringing signal generated from the signal source. A switching device is provided for each subscriber's line for connecting the telephone to the speech network or to the ringing signal sending circuit. A control device individually controls the switching device of the subscriber's line in accordance with control information from a common controller of the exchange to send out the ringing signal at required timing and for controlling the interrupting device of the ringing signal sending circuit at the time of switching of the switching device of any one of the subscriber's lines. Upon completion of terminating connection, calling can be made immediately, Further, the inter-rupting tempo of the ringing signal can be changed by the control of the common controller, so that where this system is applied to a PBX (private branch exchange), the kind of call, for example, an incoming call from the central office line or a terminating call from an extension, can be identified by the ringing signal, The ring back tone is sent out in synchronism with the ringing signal. Flip-flops for controlling the ringing signal sending circuit, the subscriber's line switching device and a ring back tone trunk are not provided basically corresponding to the capacity of the exchange, but are distributed corresponding to the above said devices to be controlled. The control informtion transferred in parallel from the common controller is once supplied to the signal distributor, and then transferred therefrom in series to each of the above said circuits or a driver of the subscriber's line switching device. As a result of this" the flip-flops can be used efficiently and increased in number easily, and the diameter of cable for the transmission of information can be reduced.</p> |
