| 摘要 |
PURPOSE:To improve the quality of service of a channel by controlling two time switches provided in a push button register and opening/closing them to control the start and end of dial tone transmission to a subscriber. CONSTITUTION:When it is detected that a pushbutton subscriber 1 hooks off a pushbutton signal from the subscriber 1 is received by a pushbutton tone receiver 20 and on the other hand, a dial tone is transmitted to the subscriber 1. When the 1st dial from the subscriber 1 is detected by a pushbutton register 19 in this state, a switch 23 is turned off and the dial tone transmission from the subscriber 1 is stopped. When all dialing from the subscriber 1 is finished for receiving, the time switches 21, 22 and a spatial switch 15 are opened and the subscriber 1 is reconnected to a prescribed path. Thus, a call connection is attained without connecting in duplication the spatial switch. |
