| 摘要 |
PURPOSE:To normally execute dial pulse reception by immediately changing a control signal for transition to an off-hook condition and changing the control signal for a fixed time longer than a dial pulse period for the transition to an on-hook condition based on the output of a subscriber line condition decision circuit. CONSTITUTION:A feeding voltage control means 19 is connected to a subscriber line condition deciding means 14 in order to immediately switch an output signal in the case of a change from the on-hook to off-hook and to change the output signal after the lapse of the fixed time in the case of the change from the off-hook to on-hook based on the output of the means 14. The output goes to be the input of a power supply voltage switching signal to a feeding power source 17. Here, by setting the fixed time of a feeding voltage control means 19 longer than the period of the dial pulse, the condition of the high power supply voltage can be continuously maintained while the dial pulse is sent. Thus, when the dial pulse is sent, a loop current much flows and the reception of the dial pulse can be made secure. |
