| 摘要 |
PURPOSE:To reduce the price of a telephone-set circuit by transmitting a dial- pulse oscillation output to a line by disconnecting a calling circuit directly, and by limiting the transistor to one in which a DC large current passes. CONSTITUTION:The pulse which is equivalent to the button input is transmitted from the oscillation output terminal of a dial-pulse oscillation circuit 3 at the time of dialing, a transistor 22 is connected or disconnected by the signal, and the dial signal is transmitted to the line by disconnecting the DC loop of a calling circuit directly. At this time, the control output terminal voltage of the dial- pulse oscillation circuit 3 becomes earth electric potential, both transistors 23 and 24 turn off, and it is prevented that dial click sound generates in the receiver 6. |
