CN2231838Y - Alarm inhibiting apparatus for preventing fraudulent use of telephone line - Google Patents

Abstract

The utility model is composed of a low-resistance detection impedance transducer, an emitter follower, a signal judgment control circuit, an inhibited signal generator, a music alarm unit, a function control unit, etc. The combination of the electronic circuit and a relay is adopted to make the logical judgment and the inhibition, the accurate identification, the alarm maintenance and to inhibit the telephone circuit being illegally embezzled. The alarm inhibiting apparatus for preventing fraudulent use of telephone line is serially connected with the telephone set to be used. As long as the fraudulent use condition appears on the telephone line, the music alarm sound can be kept until the human eliminates the music alarm sound. The alarm inhibiting apparatus for preventing fraudulent use of telephone line has the advantages of simple structure, accurate judgment, low cost, and reliable performance.

Description

Anti-warning, the inhibitor usurped of telephone line

The utility model relates to a kind of device that prevents other people illegal phreaking.

Along with the continuous development of human material progress, phone just promptly is deep in people's work, the studying and living, and private telephone also enters family more and more.But the thing followed is usurped other people telephone wire, and the vile practices of freely enjoying the phone facility also occur thereupon, and many machine main warp Chang Yaowei steal the telephone line person and pay a large amount of telephone chargess.

In view of the phenomenon that exists in the above-mentioned telephonic communication, the purpose of this utility model is that a kind of telephone line of design is prevented usurping protective device, and when telephone wire was illegally usurped by other people, the machine master can in time obtain circular, and appropriator then can't use phone to carry out communication.

The utility model has reached above-mentioned purpose of design with the design of its novelty, it is by detecting impedance transducer, emitter follower, suppress signal generator, the line function controller, signal is judged control circuit, light shows circuit, music alarm circuit and power circuit constitute, the input signal of transducer is the telephone wire input voltage signal, line function control circuit control detection impedance transducer, emitter follower is judged the control circuit isolation with transducer and signal, signal judges that the signal output part of control circuit connects optical display unit and music alarm circuit respectively, the transducing signal that the detects impedance transducer inhibition signal generator of feeding, the output signal that the suppresses signal generator signal of feeding is again judged control circuit.

Operation principle of the present utility model is: utilize low value impedance serial connection in the line as transducer, by the signal of this low value impedance, and no dial tone is arranged in the circuit, judge that the used circuit of this off-hook is that internal user uses, or outside line is used illegally.When internal user normally uses, signal judging unit work, music alarm and inhibition signal generating unit are not worked, if when having outer circuit illegally to use off-hook, detect no conversation signal voltage in the impedance, music alarm unit and the work of inhibition signal generating unit, can only hear back drop in illegal user's phone, can't converse, have only after the user finds that alarm signal is arranged, press reset switch artificially after, alarm signal can be removed.

As long as this function has guaranteed to usurp situation, both be that the user did not exist at that time, know still after waiting to return whether this circuit situation took place to usurp.

Describe the utility model in detail below in conjunction with accompanying drawing:

Fig. 1 theory diagram

Fig. 2 electrical schematic diagram

Can be seen that by figure the utility model is by detecting impedance transducer, penetrating with isolation, signal and judge that control, music alarm, inhibition signal take place, light shows unit such as indication and line function control and constitutes, detection impedance sensing unit is by resistance R ₁, R ₂, R ₃Form, when phone did not use, the voltage signal of circuit was by R ₂And R ₃Dividing potential drop obtain.When phone normally uses, R ₁Pressure drop and R ₃Dividing potential drop stack, make input BG ₁Signal constant, holding circuit is stable, and when external circuit illegally used circuit, circuit did not pass through R to the direct current that phone provides ₁, R ₁Last no loop current pressure drop, R ₁And R ₃On dividing potential drop owing to Uin reduces, BG ₁End.

Midget relay J among the figure ₁, J ₂, J ₃Also available monostable trigger-action circuit replaces, to reduce cost.

Penetrate with isolated location by BG ₁, R ₄, C ₁, R ₅, R ₆Constitute, input signal is isolated with judging control unit.

Signal judges that control unit is by BG ₂, R _7～10, R ₁₆, C ₂, C ₃, relay J ₁, J ₂, LED ₁Constitute BG ₂, R ₇, R ₈Constitute control relay circuit.When normal use, BG ₂Conducting, J ₁Adhesive, J ₂Operating current by J ₁J ₁The control of A contact, J ₂Has self-retaining function, by J ₂B finishes the contact; J ₂During action, music alarm unit and LED ₂Work.

The music alarm unit is made up of music ic 3830 and miniature piezoelectric loud speaker RL, and when usurping situation, the J2 adhesive also keeps, and loud speaker sends musical sound, just stops up to artificial elimination.Also available resolution element in this unit and buzzer constitute.Volume will be smaller and more exquisite.

Suppress signal generating unit by R _11～14, BG ₃, BG ₄, C _4～6Constitute the astatic multivibrator of no stable state, producing frequency is the square wave of 500HZ～800HZ.When circuit is judged as illegal use, this signal generator startup work, the user can connect reset switch K if use this inhibit feature ₁, this moment signal pass through C ₆Inject subscriber's line, make and to hear the signal tone song on the talk line that is articulated on this circuit and can not converse.Because it is low that this suppresses signal frequency,, thereby inhibitory action has been played in phreaking to the not influence fully of other telephone line.When the phone on-hook of illegal use circuit, this signal generator is by relay J ₁Control quits work at once.

The line function control unit is by BG ₅, R _18～22, relay J ₃Contact J ₃A constitutes, and this unit is to judge when telephone line because broken string and telecommunication department repair when adjusting shutoff signal voltage, and this unit is controlled the breaking alarm power supply automatically, treat that circuit recovers normally after, recover the warning device power supply automatically.

Light shows indicating member by LED ₁, LED ₂Constitute LED ₁Be green, be serially connected in J ₁In the loop, when green light was bright, expression was normally used; LED ₂Be redness, be serially connected in the music alarm loop that red light is bright, i.e. indication is usurped situation and is taken place.

Telephone line just often, the unloaded direct voltage Uin of phone end points is 35～45V, when receiver off-book, phone end points direct voltage is reduced to 7～10V, during on-hook, BG ₁Base stage (b) point voltage is R ₂With R ₂+ R ₁Dividing potential drop, this moment, voltage U in was higher, this dividing potential drop makes BG conducting, BG ₂The conducting adhesive, J ₂Release, BG ₃, BG ₄Working power disconnects, and does not work.

When user's off-hook, Uin voltage reduces, at this moment at BG ₁Base stage (b) some R ₂+ R ₁Dividing potential drop also decrease, be taken at R but this patent key is an end tie point with substation ₃With R ₁Between, like this, the electric current that phone passes through is at R ₁Last formation voltage drop, R ₁The current voltage drop at two ends is designed to and R ₃Dividing potential drop stack, make BG thus ₁Base voltage does not reduce down, thereby keeps user BG when off-hook is arranged ₁And all loop states are constant.

When usurping line phones (outer off-hook), Uin reduces, BG ₁Base voltage reduces, and is connected on outside the Uin and usurp phone, and the phone electric current does not pass through R ₁Thereby, BG ₁By, BG ₂End J ₁Discharge J ₂Adhesive, BG ₃, BG ₄Work, (suppressing dialing and conversation), 3830 work are reported to the police.

When usurping the phone on-hook, BG ₁Recover normally, J ₁Adhesive, BG ₃, BG ₄Quit work, and J ₂Because self-sustaining makes 3830 still to work, until the straight position of user.

The utility model has adopted the structure of electronic circuit and relay assembly to carry out logic determines control, circuit is simple, cost is low, dependable performance, telephone line is had no effect, need not safeguard, reach the optimum efficiency of Intelligent Recognition with minimum device, especially utilize low-resistance to detect that voltage drop in the impedance and subscriber signal voltage are superimposed to be judged as normal use or outside line is usurped, its judged result is very accurate and effective, is a kind of warning, inhibitor with anti-fraudulent use of telephone of functions such as identification, maintenance, warning.

The utility model product is serially connected on the telephone set and uses, and can select the AC and DC power supply as required for use, if design hanging hole on housing, then can hang on the wall, uses and can more feel convenient.

Claims (3)

1, anti-warning, the inhibitor usurped of telephone line, judge that by transducer, emitter follower, inhibition signal generator, line function controller, signal control circuit, light show circuit, music alarm circuit and power circuit and constitutes, it is characterized in that transducer is to detect impedance transducer, by R ₁, R ₂, R ₃Three sample resistances constitute, its output termination is penetrated with isolated location, penetrate with unit output and signal and judge that the control unit input links to each other, signal judges that the control unit output shows indicating circuit and links to each other with music alarm circuit with inhibition signal generator, light respectively, suppress signal generator output termination and detect impedance transducer, by sensor unit, feed back the interference suppression signal of external circuit.

2, telephone line according to claim 1 is anti-usurps warning, inhibitor, it is characterized in that signal judgement control circuit is by transistor BG ₂, relay J ₁, J ₂, R _7～10, capacitor C ₂, C ₃Constitute J ₂Be latching relay, suppressing signal generator is by BG ₃, BG ₄, C ₄, C ₅, R _11～14The multivibrator that constitutes, the line function control circuit is by BG ₅, R _18～22, relay J ₃Pair of contact constitute, detect impedance transducer by R _1～3The low-resistance bleeder circuit of forming constitutes.

3, telephone line according to claim 2 is anti-usurps warning, inhibitor, it is characterized in that R in the transducer ₁Resistance is 50 Ω, electrochemical capacitor C in the signal judging unit ₂Capacity is 2000～4000 μ F.