CN2209847Y - Protector for telephone line - Google Patents

Abstract

The utility model provides a protector for a telephone line. A line input socket, a line output socket, a printed-circuit board and an alarm circuit are arranged in a circuit box. The printed-circuit board is provided with a sample circuit, a power circuit and a controlling circuit. The protector for a telephone line not only can protect the telephone line but also can prevent the thief machine tapping. The influence on the telephone line is small. Moreover, the protector for a telephone line has acoustic-optic function, low cost, and convenient operation.

Description

Protector for telephone line

The utility model relates to a kind of telephone line protector.

A kind of telephone line protector without external power supply is arranged on the existing market; though can play the certain protection effect to telephone line; it is big that but it exists original call line influence; show that line current is not big when making a phone call; electric current is 4.5 milliamperes; line drop is big; voltage reduces 5.7V; during if oneself will make a phone call; also need open the switch of telephone line protector, to disconnect protection circuit, crafty in this case machine just can be eavesdropped; when reporting to the police, have only indicator light to report to the police in addition, and do not have musical sound to report to the police.

The purpose of this utility model is to provide a kind of can protect telephone line, can prevent crafty machine eavesdropping again, and little to the telephone line influence, and has the telephone line protector of sound and light alarm.

The mode that the utility model is realized is to be provided with a circuit input socket, a circuit accessory power outlet in a circuit box, a printed substrate and an alarm circuit, and its printed substrate is provided with a sample circuit, power circuit and a control circuit.

Advantage of the present utility model is that it not only can the reliable protection telephone line; and can prevent crafty machine eavesdropping; little to the telephone line influence; the telephone line current drain is less than 1 milliampere; telephone line voltage only reduces about 1V; and have the function of sound and light alarm, and it is easy to use, and cost is low.

Description of drawings:

Fig. 1 is an appearance assumption diagram of the present utility model;

Fig. 2 is an internal structural map of the present utility model;

Fig. 3 is circuit theory diagrams of the present utility model;

1 is lid among the figure, the 2nd, and at the bottom of the box, the 3rd, luminous tube, the 4th, buzzer, the 5th, circuit input socket, the 6th, circuit accessory power outlet, the 7th, printed substrate, the 8th, music integrated circuit plate.

The utility model is further described with embodiment below in conjunction with accompanying drawing:

The utility model circuit box is made by plastic material, it by a lid (1) and box at the bottom of (2) constitute, in the circuit box, be provided with a circuit input socket (5), circuit accessory power outlet (6), a printed substrate (7) and an alarm circuit, its printed substrate (7) is provided with a sample circuit, power circuit and a control circuit, described sample circuit is by resistance R 11, R12, R13, R14 integrated circuit (IC) 2 and capacitor C 2 are formed, the parameter of its element or model are that R11 is 150K Ω, R12 is 10K Ω, R13 is 47 Ω, R14 is 5.1K Ω, and ic chip 2 is 4N25, capacitor C ₂Be 100 μ F/25V, described power circuit is by resistance R 1, R2, R3, R4, R5, R6, transistor BG1, BG2, BG3 and voltage stabilizing didoe D1 form, its component parameters or model are that R1 is 330K Ω, R2 is 10K Ω, R3 is 220K Ω, R4 is 220 Ω, R5 is 220 Ω, R6 is 3.3K Ω, BG1, BG2, BG3 is 2N5551, D1 is 3.3V1/2W, and described control circuit is by resistance R 7, R8, R9, transistor BG4, BG5 and capacitor C 1 are formed, and its component parameters or model are that R7 is 51K Ω, R8 is 220 Ω, R9 is 3.3K Ω, and BG4 is 2N5551, and BG5 is 2N5401, C1 is 220 μ F/25V, described warning circuit is by resistance R 10, light-emitting diode D1(3), music integrated block IC 1(8) and buzzer HTD(4) form, its component parameters or model are that R10 is 220 Ω, D1 is φ 5 light-emitting diodes, IC1(8) be KD1001, buzzer HTD(4) be HTD-27.In order to prevent that overvoltage from damaging this practical circuit components and parts, also installed piezo-resistance R15 additional, model is RMZ220V, and capacitor C3 adds the cross-talk of phone in order to reduce broadcasting, its parameter is 0.1 μ F/250V, and the model of its input, accessory power outlet is 623K.

Circuit theory of the present utility model is:

1. sample circuit: utilize the variation of making a phone call Shi Tiji and not carrying voltage on the former circuit of machine to take a sample: voltage height on the circuit when not carrying machine, lie prostrate about 48-60, voltage drops to 5～12V when carrying machine, R11 and R12 are voltage sampling resistor, the voltage height of getting on the BG5 base stage when voltage is high, the voltage that the BG5 base stage was got when the voltage on the circuit was low is low, thereby changes the operating state of control circuit.C2 is for BG5 base stage sampling voltage being stablized when this machine dialing and the ring.For distinguishing this machine and crafty machine, adopted the sampling of this machine operating current again, R13 is a current sampling resistor, and the isolation of this current sampling and voltage sampling is the core of this circuit, and buffer circuit is made up of resistance R 14 and integrated circuit (IC) 2.When carrying machine, crafty machine has only voltage sampling, and the current sampling buffer circuit work that this machine is made up of R13, R14 and IC2 when carrying machine, and be connected across voltage sampling resistor R11 two ends, the BG5 base voltage is raise relatively.Existing product is made a phone call with crafty machine for this machine of difference, moves a switch when adopting this machine to make a phone call, and is very inconvenient.This circuit adopts photoelectricity coupling integrated circuit (IC2) to solve this problem dexterously, and circuit is greatly simplified, and cost reduces.

2. power circuit: existing product needs additional power source, though what have does not need additional power source, it is more that electric current is increased, and voltage reduces morely (for example has a kind of product electric current to increase by 4.5 milliamperes, voltage reduces by 5.7 volts), bigger to former line influence.This circuit has both ideally accomplished power taking from the original call circuit and the trouble of removing additional power source from drops to minimum to the influence to former circuit.Power circuit is made up of resistance R 1, R2, R3, R4, R5, R6, transistor BG1, BG2, BG3 and voltage stabilizing didoe D1, BG1 base potential height when not making a phone call, the BG1 saturation conduction is connected across former circuit two ends with R3, make BG2, BG3, BG4, BG5 all be in cut-off state, the circuit sealing.Electric current is less than 1 milliampere on the telephone line at this moment, and voltage reduces about about 1 volt.And this machine or crafty machine be when carrying machine, and the BG1 base voltage reduces, and BG1 ends, BG2, BG3 conducting, and BG3 emitter output 1.5～3.5 burning voltages are delivered to the BG5 emitter.

3. control circuit: this circuit is the executive arm of defencive function; adopted switching circuit control dialing; the conversation AC signal output and do not influence former circuit DC operation state; and this machine of making is not affected when making a phone call; and can be reliably with its target signal filter during the dialing of crafty machine; R7; R8; R9; C1 and BG4; BG5 has formed control circuit; BG5 base voltage height when not carrying machine; emitter voltage low (0 volt); BG5 ends; this moment, the BG4 base stage did not have voltage; also be in cut-off state; R7; C1 is inoperative, and the BG5 emitter voltage is higher than base voltage and conducting when carrying crafty machine, and the BG4 base stage obtains 0.7 volt of voltage and also is in the saturation conduction state simultaneously; capacitor C 1 is attempted by the circuit two ends crafty machine dialing signal is filtered, and it can't be dialled.When this machine of carrying, though the BG5 emitter voltage raises, but because the effect of R13, R14 and IC2 makes BG5 base voltage also raise (than emitter voltage height), thereby make BG5 still be in cut-off state, BG4 also ends, cause R7, C1 inoperative, dialing and conversation signal can normally pass through, and do not influence this machine and make a phone call.This circuit has the anti-eavesdrop function: pick up if any crafty machine when this machine is conversed and eavesdrop, the operating state of entire circuit is between this machine of carrying and carry crafty machine between the two, makes conversation sound very little, almost do not hear, sound and light alarm is arranged simultaneously, and reminding has the people to eavesdrop, and this machine can suspend makes a phone call.

4. warning circuit: be made up of music integrated circuit IC1, buzzer HTD and light-emitting diode D2, the BG5 conducting has electric current to flow through on the D2 when crafty machine dialing and eavesdropping, and D2 is luminous, and IC2 powers up work simultaneously, and buzzer is named loud, accomplishes that acousto-optic reports to the police simultaneously, and power consumption is little.

Claims (1)

1. A kind of telephone line protector; it is characterized in that it is to be provided with a circuit input socket (5) in a circuit box; a circuit accessory power outlet (6); a printed substrate (7) and an alarm circuit; its printed substrate (7) is provided with a sample circuit; power circuit and a control circuit; described sample circuit is by resistance R 11; R12; R13; R14; integrated circuit (IC) 2 and capacitor C 2 are formed; described power circuit is by resistance R 1; R2; R3; R4; R5; R6; transistor BG1; BG2; BG3 and voltage stabilizing didoe D1 form; described control circuit is by resistance R 7; R8; R9; transistor BG4; BG5 and capacitor C 1 are formed, and described warning circuit is by resistance R 10; light-emitting diode D1 (3) music integrated block IC 1 (8) and buzzer HTD (4) form.

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