JPS6416755U

JPS6416755U -

Info

Publication number: JPS6416755U
Application number: JP11182987U
Authority: JP
Priority date: 1987-07-21
Filing date: 1987-07-21
Publication date: 1989-01-27

Description

[Brief explanation of the drawing]

第１図は本考案のミスダイヤル防止回路の一実
施例を備えたオンフツクモニター機能付電話機の
回路構成図、第２図は従来のオンフツクモニター
機能付電話機の回路構成図である。主な図番の説明、３７…第１トランジスタ、３
９…第２トランジスタ、４１…コントロール回路
、４３…フツクスイツチ、４４…操作スイツチ、
４５…ダイヤル信号発生回路、５０…第３トラン
ジスタ、５２…ツエナーダイオード。 FIG. 1 is a circuit diagram of a telephone with an on-hook monitor function equipped with an embodiment of the misdial prevention circuit of the present invention, and FIG. 2 is a circuit diagram of a conventional telephone with an on-hook monitor function. Explanation of main figure numbers, 37...first transistor, 3
9... Second transistor, 41... Control circuit, 43... Hook switch, 44... Operation switch,
45...Dial signal generation circuit, 50...Third transistor, 52...Zener diode.

Claims

[Scope of utility model registration request]

A telephone circuit that performs a telephone call operation with a diode bridge circuit connected to the telephone line in a telephone set having a function of closing a telephone line by operating a control switch or detecting a ringer signal, etc., regardless of the opening/closing operation of a telephone switch. a first transistor that is connected between the telephone line and performs an opening/closing operation for the telephone line; a second transistor that controls the operation of the first transistor; and a second transistor that corresponds to the operation of the operation switch or the ringer signal detection operation. a control circuit that controls a second transistor and turns on the first transistor; and a dial signal generation circuit that applies an output signal to the second transistor similarly to the control circuit and causes the first transistor to operate to send a dial signal. , a Zener diode connected in parallel to the telephone line between the diode bridge circuit and the first transistor to perform a voltage limiting operation on the telephone line; a third transistor for controlling the operation of the Zener diode; and a voltage detection circuit connected in parallel between the first transistor and the telephone circuit to receive the voltage between the telephone lines and control the operation of the third transistor, so as to prevent abnormal dialing signals from being sent out during the dialing signal sending operation. A misdial prevention circuit for a telephone set.