| 摘要 |
PURPOSE:To simplify unholding operation by hooking a hand set on a telephone set body so as to be held most stably at the holding state. CONSTITUTION:If the telephone set to be set in the holding status during talking, a holding switch 10 arranged on the upper surface of a holding adaptor A is depressed to turn on contacts 10a, 10b. Consequently, a telephone circuit 1 is closed by the contact 10a and the secondary winding N2 of a transformer 12, a DC loop is formed and the circuit 1 is set up to the holding status. Simultaneously, a power supply circuit 13 to be controlled by the contact 10b is actuated, power is supplied to a holding tone generating circuit 11, and a holding tone signal generated by the circuit 11 is sent to the circuit 1 through the transformer 12 to inform the holding status to the originator. In addition, a holding tone is generated from a speaker 14 to inform the holding status of the telephone set 2. |
