CN2279039Y - Theftproof protector for telephone line - Google Patents

Abstract

The utility model relates to an electronic device used for protecting telephone lines from being stolen. A switch circuit and a bleeder circuit which are controlled by a phone are arranged between terminals of house lead-in lines, the output of the switch circuit and the bleeder circuit is connected with an input end of a separate-excited vibrator, vibration output pushes a light emitting diode through a driver and controls a charging switch tube, and a charging circuit of the circuit provides power supplies for an integrated circuit of the device. The utility model has the advantages that when the lines are used by being stolen, the protector causes line voltage to be periodically changed, which causes phones that are stolen can not dial.

Description

A kind of telephone line is prevented the steal protector

The utility model belongs to telephone plant, particularly relates to the anti-steal protector of a kind of telephone line.

Existing simple type telephone line is prevented the steal device, can only be to stealing machine output interference signal, and for example musical sound or intermittent noise, but be not enough to stop the machine of stealing to use, particularly double-tone are stolen machine frequently still can number dialing telephone call in music or noise gap.

The purpose of this utility model provides the anti-steal protector of a kind of telephone line that the machine of stealing can't be dialled.

Above-mentioned purpose is obtained by following technical scheme: protector housing (3) two ends are respectively equipped with terminal B3; B4 and terminal B1; B2; terminal B2; B4 joins; terminal B3; be connected between the B4 by voltage stabilizing didoe CW; resistance R 4; the dividing potential drop branch road that R5 contacts mutually; resistance R 5 two ends also meet filter capacitor C1; resistance R 4; the dividing point a that R5 joins connects external excited oscillation device input; its output termination driving transistors T3b utmost point; the transistor T 3c utmost point through light-emitting diode L1 to terminal B3; transistor T 3e utmost point connecting terminal B4; charging capacitor C2 two ends and connecting resistance R2; capacitor C 2 negative terminal connecting terminal B4; the positive termination switching transistor T2c utmost point; e utmost point connecting terminal B3, the b utmost point meets the driving transistors T3c utmost point, switching transistor T2e through base resistance R1; be connected to resistance R 3 between the c utmost point; terminal B1 connects the switching transistor T1b utmost point; e utmost point connecting terminal B3, the c utmost point meets dividing point a through resistance R 6, transistor T 1b; be connected to base resistance R7 and diode D1 between the e.

Each components and parts of the splicing ear B4 of foregoing circuit can join with isolating diode D2 anode, its negative terminal splicing ear B4.

Further specify the utility model with drawings and Examples below.

Accompanying drawing 1, the utility model electrical schematic diagram:

Accompanying drawing 2, the utility model external form schematic diagram.

Drawing explanation: 1 substation line, 2 circuit boards, 3 protector housings, 4 light-emitting diode L1,5 house lead in circuits.

Operation principle of the present utility model as shown in Figure 1, terminal B3, the 48V direct voltage of being sent here by switch is arranged between the B4, terminal B1, B2 connects substation, terminal B3, when not having the machine of stealing between the B4, the voltage stabilizing value is that the voltage-stabiliser tube CW two ends constant voltage of 20V is 20V, the about 9V of dividing point voltage magnitude of voltage, by NAND gate circuit N1, N2 feedback resistance R9, R10, the external excited oscillation device that isolating diode D3 and charging capacitor C3 constitute is not worked, and the C point is a high level, through NAND gate N3, N4 is anti-phase, the d point is a low level, transistor T 3 ends, and light-emitting diode L1 does not work, terminal B3, keep 48V voltage between the B4.

User's off-hook, switch transistor T 1 conducting, voltage is clamped at 10V between terminal B3, the B4, and voltage-stabiliser tube CW ends, and the level of dividing point a still is a high level by switch transistor T 1 decision of conducting.At this moment, driving transistors T3 still ends, but user's normal talking.

When the machine of stealing is connected on terminal B3, B4 and off-hook, the substation on-hook, terminal B3, B4 are clamped at 10V equally, voltage-stabiliser tube CW and switch transistor T 1 are all ended, and dividing point a is a low level, and the anti-phase d point of the NAND gate N3 through being in parallel, N4 is a high level, driving tube T3 conducting, light-emitting diode L1 is bright, between terminal B3, the B4 only there is about 1.5V voltage, and the machine of stealing can not dial because of brownout.Charging capacitor C3 is via resistance R 9, NAND gate N2 internal discharge subsequently, the B level point descends gradually, when dropping to the N2 threshold voltage, the c level point is uprised by low, and d point output low level, transistor T 3 is ended, voltage returns to 10V between terminal B3, the B4, the c level point rises the b level point via diode D3 resistance R 10 to capacitor C 3 chargings again, during to NAND gate N2 threshold voltage, the c point voltage makes transistor T 3 conductings by high step-down, thus repeatedly, between terminal B3, B4, form a consecutive pulses signal, make when surreptitiously machine can not dial and to converse.

When switch transistor T 2 is flat in the circuit is conducting state, make capacitor C 2 chargings, when driving tube T3 conducting, switch transistor T 2 is ended, prevent capacitor C 2 outside circuit dischargings, and only provide voltage to keep NAND gate N1-4 integrated circuit operate as normal, because charging capacitor C2 appearance value is far longer than charging capacitor C3, and switch transistor T 2 is on off state, and e point voltage value is remained unchanged substantially.

The each point of answering splicing ear B4 in the circuit is all through isolating diode D2, and circuit could operate as normal when the house lead in circuit correctly was connected with each terminal, and diode D2 ends during reversal connection, and does not damage each components and parts.

The utility model has the advantages that, during the substation on-hook, the machine of stealing can't dial and Continuous impulse disturbs and can't use, and has simultaneously that light emitting diode is glittering warns.

Claims (2)

1; a kind of telephone line is prevented the steal protector; by housing; terminal; wiring board is formed; it is characterized in that: the housing two ends are respectively equipped with terminal B3; B4 and terminal B1; B2; terminal B2; B4 joins; terminal B3; be connected between the B4 by voltage stabilizing didoe CW; resistance R 4; the dividing potential drop branch road that R5 contacts mutually; resistance R 5 two ends also meet filter capacitor C1; resistance R 4; the dividing point a that R5 joins connects external excited oscillation device input; its output termination driving transistors T3b utmost point; the T3c utmost point through light-emitting diode L1 to terminal B3; T3e utmost point connecting terminal B4; charging capacitor C2 two ends and connecting resistance R2; its negative terminal connecting terminal B4, the positive termination switching transistor T2c utmost point, e utmost point connecting terminal B3; the b utmost point connects the driving transistors T3c utmost point through base resistance R1; switching transistor T2e; be connected to resistance R 3 between the c utmost point, terminal B1 connects the switching transistor T1b utmost point, e utmost point connecting terminal B3; the c utmost point meets dividing point a through resistance R 6, transistor T 1b; be connected to base resistance R7 and diode D1 between the e.

2, protector as claimed in claim 1 is characterized in that: each components and parts of splicing ear B4 can join with isolating diode D2 anode, its negative terminal splicing ear B4.

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