CN2266232Y - Telephone network device for preventing fraudulent use - Google Patents

Abstract

The utility model discloses a telephone-network anti-theft device, characterized in that the telephone-network anti-theft device is provided with a sampling and a comparing circuits; the telephone network is connected with a subscriber telephone via the sampling and the comparing circuits. A dc electronic switching circuit also connected with the telephone network is connected with the sampling and the comparing circuits. An electronic switching circuit connected with the sampling and the comparing circuits and the electronic switching circuit is connected with an alarm circuit. The utility model has the advantages of low cost and easy installation, can effectively prevent telephone lines from being stolen and send out alarm signals in time, without no influence on users' normal use.

Description

The telephone network antitheft device

The utility model relates to the device that the user in the telephone communication uses, and is a kind of calling or false device of calling out that prevents without permission that have.

Along with the raising of science and technology development and living standards of the people, phone has entered huge numbers of families, becomes the important tool of transmission information, the good companion of family life.Because existing phone networking has and anti-usurps device, thus steal other people the thing at phone networking happen occasionally, cause economic loss to the telephone subscriber.

The purpose of this utility model provides a kind of simple in structure, easy for installation, telephone network antitheft device that can prevent the stolen usefulness in phone networking.

Technical solution of the present utility model is: a kind of telephone network antitheft device, adopted the design that does not have in the prior art: a sampling is arranged, comparison circuit, the phone networking links to each other with substation through sampling, comparison circuit; One also links to each other with sampling, comparison circuit with the electronic DC switch circuit that the phone networking joins; An electronic switching circuit that joins with sampling, comparison circuit and electronic DC switch circuit is connected to warning circuit.

Electronic DC switch circuit described in the utility model also is connected to working indicating.

Electronic DC switch circuit described in the utility model, and sampling, comparison circuit and electronic switching circuit be integrated into an application-specific integrated circuit (ASIC).Certainly, also can adopt the discrete element structure form.

Application-specific integrated circuit (ASIC) described in the utility model adopts plastic packaging or the soft packaging appearance of printed substrate.

Sampling described in the utility model, comparison circuit are connected to reset switch.

The utility model has the advantages that: profile can adopt the structure similar with the telephone connection box; easy for installation; after loading onto; in a single day telephone line has people's steal, can bring into play defencive function immediately, and send alarm signal; remind the user; the steal phone can't be worked, the outwards number of sending out or conversation, thus prevented that effectively user telephone line is by other people steal.And user's phone is used the nothing influence.Circuit structure is simple, and owing to can adopt the form of application-specific integrated circuit (ASIC), adds the assembling of small number of external element, makes production and use all very easy, the reliability height.Help the simplification of production technology and the raising of product quality and output.The utility model cost is low, is no more than 10 yuan, is beneficial to and applies.

The utility model is described in further detail below in conjunction with drawings and Examples:

Fig. 1 is the functional-block diagram of a kind of telephone network antitheft device of the present utility model.

Fig. 2 is the electrical schematic diagram of Fig. 1.

Fig. 1 has described operation principle of the present utility model.The netting twine road L1 of telephone office, L2 link to each other with substation behind sampling, comparison circuit 2.The netting twine road L1 of office, L2 also are input to electronic DC switch circuit 1 simultaneously, provide the dc supply of sampling, comparison circuit 2, electronic switching circuit 3, alarm call 4 and working indicating 5 to carry out the work indication then.

At the substation hook state or carry machine when conversation, electronic DC switch circuit 1 is in opening state, makes other partial circuit operate as normal.When circuit had bell signal, electronic DC switch circuit 1 was closed rapidly, and other circuit wouldn't be worked.So ring does not have influence to substation, has protected the safety of other circuit simultaneously, in case by the alternating voltage punch through damage about 90V.The phone networking is through sampling, comparison circuit 2, and sampling, comparison circuit 2 can take a sample the variation in the netting twine exactly, relatively amplify, and control electronic switching circuit 3 and warning circuit 4 then.When electronic switching circuit 3 was operated in waiting state, the user can normally carry out all talk activities, in case electronic switching circuit 3 work can make the steal phone outwards dial and to converse.During warning circuit 4 work, sound the alarm, note with the caution user.

Fig. 2 has described an embodiment of the present utility model.Subscriber's telephone line L1, the L2 end 48V one 60V office net voltage of program controlled telephone office output at first is input to the electronic DC switch circuit of being made up of triode VT1, controllable silicon VT2, resistance 1R1, diode VD1.When L1 end polarity is timing for negative, L2 end, triode VT1 obtains the forward bias voltage of resistance 1R1 input and works, export a voltage at its emitter, promote controllable silicon VT2 conducting, at one of the K of controllable silicon VT2 utmost point output and L2 end same polarity voltage, the L1 end is in a ratio of negative polarity with the L2 end, so diode VD1 forward conduction, guarantee the quality of the DC power supply of electronic DC switch output, improved the functional reliability of integrated circuit.Diode VD2-VD7, triode VT3, VT4, resistance 1R2-1R5 and resistance R 1 are formed the sampling comparison circuit; Resistance R 2, light-emitting diode VD8 form working indicating.Electronic DC switch is in a single day working properly, and luminous tube VD8 is operate as normal by the metering function of resistance R 2, and luminous, and is normal to show circuit working.Tens volts of voltages of controllable silicon VT2K utmost point output are added on diode VD2, VD3, the resistance 1R3 network.Diode VD2 carries out voltage sampling.As diode VD2 and during conducting by high voltage institute " puncture ", diode VD3 is forward conduction also, resistance 1R3 forms the work loop, form a new magnitude of voltage at diode VD3 negative pole end, be defeated by triode VT4 by resistance 1R4, triode VT4 conducting, its collector electrode is output as zero potential, and the back level is not worked.At this moment, circuit is in the wait state of thief-proof warning, and subscriber phone also is in hook state.Carry machine as the user, because the work of phone is reduced to about 10 volts tens volts of voltages, diode VD2, VD3 end, and triode VT4 does not have positively biased also can be ended.But carry machine in a flash the user, sample resistance R1 goes up and produces voltage drop, be added in b, the e utmost point of triode VT3 by diode VD5, VD6 and VD4, Ub＜Ue value, triode VT3 conducting, its collector electrode makes triode VT4 still keep conducting state by voltage of diode VD7 output, and warning circuit is not worked.The user can normally carry out communications activity.Because the sample resistance resistance is very little, so user's communication is not had obvious influence.This moment, luminous tube VD8 extinguished, and was among the normal talking to show circuit.Extremely go up and connect capacitor C 1 at b, the c of triode VT4, play delayed action, can improve the functional reliability of circuit.Triode VT5-VT7 forms electronic switching circuit, in case during other people steal phone network, UL2 ↓ → UVT2, K ↓ → UVT4, b ↓ → UVT4, c ↑, on triode VT4 collector electrode, produce driving voltage, impel electronic switch circuit for working, phone network voltage is dragged down, and net voltage is about the Uce sum (because of current limiting element is arranged in the phone network, so do not influence programme-controlled operate as normal) of the Ube+ triode VT7 of triode VT5 at this moment.This moment, L1, L2 terminal voltage were very low, and the steal phone can't be worked.Triode VT5 collector electrode is exported a voltage simultaneously, and the filter action by capacitor C 2 offers warning circuit.The core of the part of reporting to the police is a common product warning circuit piece.Warning circuit obtains operating voltage, starts working, and sounds the alarm among the loud speaker Y.Resistance R 5 plays adjusts the speaker volume effect, plays the booster action of triode VT7 simultaneously.When telephone set is normally proposed the machine conversation, consume about the about 40mA of phone network power supply; Antitheft device is in the alarm condition, consumes about the about 45mA of phone network power supply, so long-time the warning do not have influence to phone network.Press and touch reset key AN, chimes of doom is removed.When two contacts of reset key AN contact, L2 carries a voltage by AN to triode VT4 base stage, makes the cut-off state of triode VT4 among reporting to the police become conducting state, and electronic switch quits work, antitheft device returns in the wait work, and luminous tube VD8 lights again.Also have resistance R 3, elements such as R4, triode VT8 in the circuit.

When ring, alternating voltage is added on the electronic DC switch circuit, and what triode VT1 base stage obtained is alternating voltage, so triode VT1 can't work and end, controllable silicon VT2 also and then ends, and VT2 is output as zero.So when phone network had bell signal, antitheft device did not produce shunting action to alternating voltage, and the ring of subsets is not had influence.

Present embodiment adopts application-specific integrated circuit (ASIC) and small number of external element to assemble.Among Fig. 2 in the square frame shown in element be the IC interior element, this application-specific integrated circuit (ASIC) can adopt plastic packaging or two kinds of contour structures of the soft encapsulation of printed substrate, outer lead all can have 10 (wherein one is test lead), lead-in wire number puts in order and can do corresponding change according to producing needs, but built-in function is constant.

The utility model profile can be made into plain old telephone terminal box style.Open loam cake, can see four terminals up and down, be respectively applied for answer the call netting twine and substation line.

Claims (5)

1, a kind of telephone network antitheft device is characterized in that: a sampling is arranged, and comparison circuit, the phone networking links to each other with substation through sampling, comparison circuit; One also links to each other with sampling, comparison circuit with the electronic DC switch circuit that the phone networking joins; An electronic switching circuit that joins with sampling, comparison circuit and electronic DC switch circuit is connected to warning circuit.

2, telephone network antitheft device according to claim 1 is characterized in that: described electronic DC switch circuit also is connected to working indicating.

3, telephone network antitheft device according to claim 1 and 2 is characterized in that: described electronic DC switch circuit, and sampling, comparison circuit and electronic switching circuit be integrated into an application-specific integrated circuit (ASIC).

4, telephone network antitheft device according to claim 3 is characterized in that: described application-specific integrated circuit (ASIC) adopts plastic packaging or the soft packaging appearance of printed substrate.

5, telephone network antitheft device according to claim 1 and 2, it is characterized in that: described sampling, comparison circuit are connected to reset switch.

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