| 摘要 |
PURPOSE:To prevent effectively a malicious call and a call from an undesired caller by setting a pass word in addition to a subscriber telephone number and confirming the pass word so as to exclude automatically a call from a person other than those knowing the pass word. CONSTITUTION:When a call takes place to a line 1 to a subscriber of a telephone set 3, a control section 28 responds to it, connects a voice response section 23 to the line and requests the transmission of a number being the pass word to the caller in voice. The pass word of the number by a voice transmitted from the caller is received by the voice response section 23, the pass word of the number in voice is converted into a digital signal, stored in a register 101 of the control section 28, compared with the pass word stored in a register 102 so as to check whether they are coincident with each other or not. When it is confirmed that they are coincident as the result of pass word check, a line control section 24 is activated and a call signal is transmitted to the telephone set 3. |
