CN2249468Y

CN2249468Y - Telephone anti-theft alarm

Info

Publication number: CN2249468Y
Application number: CN 95228563
Authority: CN
Inventors: 李逢天
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-12-28
Filing date: 1995-12-28
Publication date: 1997-03-12
Anticipated expiration: 2005-12-28

Abstract

The utility model relates to a telephone burglar alarm, including input circuit, the ringing detects/protection circuit, eavesdrops monitoring circuit, and the line of stealing is kept watch on interference circuit and local conversation detection circuitry. The utility model discloses utilize the setting to monitor the performance that the silicon controlled rectifier cutoff current is little in disturbing circuit and eavesdropping monitoring circuit stealing the line, can make static access electric current be less than 0.5 mu A.

Description

The phone burglar alarm

The utility model relates to a kind of phone burglar alarm, particularly a kind of static phone burglar alarm that inserts electric current less than 0.5 μ A.

The phone burglar alarm is a kind of device that prevents other people parallel operation conversation on subscriber's telephone line, and it can prevent effectively that the phenomenon of telephoning illegally from taking place.But the static access of existing phone burglar alarm current ratio is bigger, has influenced the communication quality of telephone network.Influence the test of telephone office to substation.

The purpose of this utility model provides a kind of phone burglar alarm that can make static access electric current less than 0.5 μ A.

Another purpose of the present utility model provides a kind of static electric current that inserts less than 0.5 μ A and phone burglar alarm with anti-eavesdrop function.

The purpose of this utility model mainly is by the control controllable silicon its static state (not stealing line) to be ended, and dynamically (robber's line) conducting realizes.

The utility model comprises: input circuit, and ring detection/protective circuit, the eavesdropping monitoring circuit is stolen line monitors interference circuit and this machine conversation testing circuit; The input and the telephone line of input circuit join, and the input of its output and bell detection/protective circuit joins; Eavesdropping monitoring circuit and robber's line monitors interference circuit are attempted by the output of ring detection/protective circuit respectively; The input and the telephone line of this machine conversation testing circuit join, and output and our phone join, and it detects output and joins with the detection receiving terminal of stealing line monitors interference circuit and eavesdropping monitoring circuit respectively.

Steal in line monitors interference circuit and the eavesdropping monitoring circuit because controllable silicon is separately positioned on, so just can utilize controllable silicon to end the little characteristic of leakage current and guarantee that the static electric current that inserts is less than below the 0.5 μ A.

The utility model has the advantages that: during user's on-hook, static state inserts electric current less than 0.5 μ A, (being about 0.3-0.5 μ A during room temperature); During user's communication, the static electric current that inserts is less than 1 μ A; Can eavesdrop prison in real time and show, if there is eavesdropping to show at once.

Below in conjunction with accompanying drawing the utility model is described in detail.

Fig. 1 is a circuit block diagram of the present utility model;

Fig. 2 is a kind of circuit diagram of the present utility model;

Fig. 3 shows second kind of structure stealing line monitors interference circuit;

Fig. 4 shows the structure of using switch to substitute the robber's line monitors interference circuit and the eavesdropping monitoring circuit of this machine conversation testing circuit;

Fig. 5-Fig. 7 shows the structure of other three kinds of input circuits and ring monitoring/protective circuit;

Fig. 8-Figure 10 shows other three kinds of structures of stealing line monitors interference circuit.

Fig. 1 has shown overall technical architecture of the present utility model.The input and the telephone line of input circuit 1 and this machine conversation testing circuit 5 join; The input of the output of input circuit 1 and ring detection/protective circuit 2 joins; The two ends (input/output terminal) of robber's line monitors interference circuit 3 and eavesdropping monitoring circuit 4 and the output of ring detection/protective circuit 2 also connect; The detection output of this machine conversation testing circuit 5 joins with the detection receiving terminal of stealing line monitors interference circuit 3 and eavesdropping monitoring circuit 4 respectively.Input circuit 1 is finished the function of overvoltage protection and polarity of voltage conversion; Ring detection/protective circuit 2 detects bell signal to prevent that bell signal is to stealing the interference of line monitors interference circuit 3 and eavesdropping monitoring circuit 4; Steal line monitors interference circuit 3 and when (line) phenomenon appears usurping in circuit, send interference signal to prevent to steal line and indication; Eavesdropping monitoring circuit 4 (during user's communication) when the eavesdropping situation occurring sends alarm signal; This machine conversation testing circuit 5 sends out-of-work signal and sends the signal of starting working for eavesdropping monitoring circuit 4 for respectively when this machine user's communication robber's line monitors interference circuit 3.

Fig. 2 has shown circuit structure of the present utility model, and in the drawings, input circuit 1 comprises piezo-resistance Ru, voltage-stabiliser tube W1 over-voltage protector and the polarity of voltage change-over circuit that is made of rectifier bridge BG1.Ring detection/protective circuit is by rectifier bridge BG2, triode N1, N2 and capacitor C 1-C3, and resistance R 1-R3 forms, and the course of work is: during no ringing signal, voltage is 0 on the capacitor C 1, triode N2 ends, and the N1 conducting provides the working power of failing the output of people's circuit to circuit 3 and circuit 4; When ringing signal was arranged, C1 was recharged, and the N2 conducting ends N1, cut off the working power of circuit 3, circuit 4.Steal line monitors interference circuit 3 by triode N3, N4, N5, P1, voltage stabilizing didoe W2, diode D1, optocoupler receiving tube NG1s, controllable silicon G1, resistance R 5-R9, capacitor C 5, C6, active buzzer Beep, light-emitting diode L1 forms; Wherein the circuits for triggering of the controllable silicon G1 that is made up of P1, C5, C6, R6, R7, W2 are connected on the output stage (emitter or collector electrode) of the triode N1 of ring detection/protective circuit 2; Multiple tube N3, N4 penetrate, collect in the path that is serially connected in controllable silicon G1 in the path; Optocoupler receiving tube NG1s is connected between the base stage and ground of multiple tube N3, N4; The biasing resistor R9 of triode N5 is serially connected in the path of controllable silicon G1, light-emitting diode L1 and buzzer Beep and connect after be serially connected in triode N5 collection one penetrate on the path.The course of work of this circuit is: when not having the line of robber, P1 ends, and G1 is by ending N5, and L1, Beep do not work.When the line of robber is arranged, because line voltage distribution reduces, charging voltage on the capacitor C 5 is higher than the P1 base voltage, and the P1 conducting triggers the G1 conducting, make the N5 conducting, thereby L1 is lighted, and the Beep sounding is because L1 and Beep parallel impedance are very low, therefore line voltage distribution is pulled down to below the 5V, make steal the line phone can't operate as normal.Optocoupler receiving tube NG1s receives the signal that the luminous tube NG1f in this machine operation detection circuit sends, and NG1s conducting when this machine user's communication ends multiple tube N3, N4, and then controllable silicon G1 is turn-offed, thereby has prevented the interference to this machine user.Eavesdropping monitoring circuit 4 is made up of triode P2, P3, light-emitting diode L2, diode D2, optocoupler receiving tube NG2S, controllable silicon G2, resistance R 10-R14, capacitor C 4, C7.Wherein optocoupler receiving tube NG2s is serially connected in during current supply circuit adds, and C4, P3, R13, R12 form the circuits for triggering of controllable silicon G2; P2, R10 form the breaking circuit of controllable silicon G2.Its operation principle is: during the conversation of this machine, and the NG2s conducting, to capacitor C 7 chargings, the e of triode P3, b tie instead partially power supply by C4, D2, R14, and P3 ends, and controllable silicon turn-offs, and L2 does not work; As eavesdropping this moment, line voltage distribution descends, and the voltage of C7 can not descend immediately, and C7 charges to C4 through R14, makes a of P3, and b ties positively biased, and the P3 conducting triggers G2 and lights L2, provides the eavesdropping indication; After eavesdropping stops, because of line voltage distribution is higher than the voltage of C7, the P2 conducting, to the G2 shunting, G2 ends because of electric current is too small, and L2 extinguishes.This machine operation detection circuit is made up of the luminous tube NG1f, the NG2f that are connected between circuit and the subscriber phone, and NG1f, NG2f are luminous when this machine is conversed makes corresponding optocoupler receiving tube NG1s, NG2s conducting.Be provided with the self-checking circuit of forming by K switch 1, resistance R 15 in addition.

Fig. 3 shows the another kind of line of stealing and detects interfered circuit 3, and be with the difference of circuit 3 among Fig. 2: replace triode N3 by triode N6, N4, N6 are serially connected in the electric power loop of this circuit, and optocoupler NG1s is connected between the base stage and ground of N6.N6 only prevents the interference of interference signal to this machine owing to the NG1s conducting ends when this machine is conversed.

Robber's line that it is set specific frequency signal that Fig. 8,9,10 shows three kinds of interference signals detects the circuit structure of interfered circuit 3.The difference of interlock circuit is among circuit shown in Figure 8 and Fig. 2: light-emitting diode L1 is serially connected in the controllable silicon G1 path, use by triode P5, N7, the oscillator that piezoelectric buzzer C9, inductance L, resistance R 19, capacitor C 8, C10 form replaces buzzer Beep, promptly this oscillator be serially connected in triode N5 collection, penetrate in the path, between power positive end and controllable silicon G1 negative electrode, insert one by triode P4, resistance R 17, the controllable silicon breaking circuit that voltage-stabiliser tube W3 forms, the effect of W3 is to prevent oscillator signal misleading to P4.For oscillating circuit, regulate the value of R19, C8, L, make its vibration in the group of frequencies of dual-tone multifrequency on some frequencies, in order to the dialing of stealing the line phone is disturbed, making switch can't differentiate institute dials the number, but also can establish three oscillating circuits, make it be operated in 1209Hz, 1336Hz respectively, 1477Hz, the wire robber just can't use the filter method filtering interfering like this, if he carries out filtering to these three frequencies, he can not transfer to any one 0-9 number so.The operation principle of circuit 3 is basic identical with the operation principle of Fig. 2, but owing to be provided with the controllable silicon breaking circuit, can make to automatically shut down controllable silicon G1 after surreptitiously line stops, after promptly stealing line and stopping, because line voltage distribution raises, the P4 conducting ends G1, L1 extinguishes, and N5 ends, the oscillating circuit failure of oscillation.The main distinction of Fig. 9 and Fig. 8 circuit is a breaking circuit of having cancelled controllable silicon G1, has cancelled voltage-stabiliser tube W2.Figure 10 shows the structure of preferable robber's line monitors interference circuit, and in the drawings by triode P1, diode D1, voltage-stabiliser tube W2, resistance R 6, R7, R8, the thyristor gating circuit that capacitor C 5, C6 form is connected between the control utmost point of power positive end and controllable silicon G1; Oscillating circuit 3-1 is connected between power positive end and the silicon controlled anode; By optocoupler receiving tube NG1s multiple tube N3, N4, resistance R 5, R20 form this machine conversation anti-clutter circuit, and the collection of its multiple tube N3, N4, emitter-base bandgap grading path are connected in series with controllable silicon G1 path.Its operation principle and foregoing circuit are basic identical.

Fig. 4 shows and adopts hand switch K2, K3 replaces luminous tube GN1f, GN2f and robber's line monitors interference circuit, the robber in this machine operation detection circuit to listen the NG1s in the monitoring circuit, the circuit structure of NG2s, K switch 2, K switch 3 are serially connected in respectively to be stolen line monitors interference circuit 3 and steals the power input of listening monitoring circuit 4.Only be to steal in the line monitors interference circuit 3 with the difference of circuit shown in Figure 2 and cancelled multiple tube N3, N4, the anode of controllable silicon G1 directly and the make contact of K switch 2 join.The operation principle of this circuit is identical with circuit shown in Figure 2.

Fig. 5-Fig. 7 shows the input circuit and the ring detection/protective circuit of three kinds of other forms; In Fig. 5, finish the function of rectifier bridge BG1, BG2 among Fig. 2 simultaneously with rectifier bridge BG1.Be that ring detecting circuit keeps capacitor C 1, current-limiting resistance R2, switch triode N2 by voltage-stabiliser tube W1, bleeder resistance R3, filtering, triode N1, biasing resistor R1 polarity protection diode D5 forms, and is connected on the output of the reversal bridge BG1 in the input circuit 1.Its operation principle is, when 1. not having ringing-current, W1 does not puncture because of line voltage distribution lower (48-60V) voltage-stabiliser tube, and C1 voltage is 0, and N2 ends, the N1 conducting is

circuit

3,4 power supplies, when 2. ringing-current being arranged, because of ringing voltage higher (25Hz, effective value 75V), W1 is breakdown, and to the C2 charging, the N2 conducting ends N1.Circuit shown in Figure 6 has been cancelled rectifier bridge BG1, BG2, increased-individual by K switch 4, the polarity identification circuit that luminous tube L3 resistance R 16 is formed is so that by the correct wiring of polarity identification, be to have increased polarity protection diode D7 in the ring detection/protective circuit with the difference of Fig. 5; The input of this circuit directly is connected on the piezo-resistance Ru two ends of input circuit.The same Fig. 5 of operation principle.Circuit shown in Figure 7 has been cancelled polarity transformation circuits BG1, has increased the polarity identification circuit (not shown) among Fig. 6, and its oscillation test/protective circuit and circuit shown in Figure 2 are identical.

Above description of contents formation of the present utility model and operation principle, be not difficult to find out owing to be provided with controllable silicon G1, G2, make of the present utility model static insert electric current can be less than 0.5 μ A.

Be briefly described the utility model course of work in conjunction with Fig. 2 more below.

When 1. not stealing line, line voltage distribution higher (48-60V), the N1 conducting, P1 is by (base stage, emitter-base bandgap grading idiostatic), and G1 turn-offs, and N5 ends, and L1 is not luminous, and Beep is sounding not.

When 2. the line of robber is arranged, line voltage distribution lower (8-12v), the N1 conducting is because the charging voltage of C5, P1 positively biased, P1 conducting, G1 triggering and conducting, N3, N4 conducting, N5 conducting, L1 is luminous, and the Beep sounding reduces voltage between lines greatly because the parallel impedance of L1, Beep limit is low, makes to usurp phone and can not dial.

3. in this machine when work, because the NG1s conducting, dragged down the base potential of N5, and when G1 was triggered, N3, N4 can not conductings, and N5 is ended, and make L1 not luminous, and Beep is sounding not, has prevented the influence of this machine conversation.

When 4. this machine was worked, because the NG2s conducting makes the eavesdropping monitoring circuit get electric work, if the eavesdropping phenomenon, line voltage distribution further reduced, and the charging voltage on the C7 makes the P3 conducting, triggers the G2 conducting, and L2 is luminous, tells owner to have the people to eavesdrop; After eavesdropping disappeared, the P2 conducting was turn-offed G2, and L2 extinguishes.

When 5. receiving bell signal, the N2 conducting drags down the N1 base potential, and N1 ends, and has prevented that bell signal is to stealing the interference of line supervision/protective circuit.

Claims

1. a phone burglar alarm is characterized in that comprising input circuit, ring detection/protective circuit, and the eavesdropping monitoring circuit is stolen line monitors interference circuit and this machine conversation testing circuit; The input and the telephone line of input circuit join, and the input of its output and ring detection/protective circuit joins; Eavesdropping monitoring circuit and robber's line monitors interference circuit are attempted by the output of ring detection/protective circuit respectively; The input and the telephone line of this machine conversation testing circuit join, and its output and our phone join, and it detects output and joins with the detection receiving terminal of stealing line monitors interference circuit and eavesdropping monitoring circuit respectively.

2. phone burglar alarm according to claim 1 is characterized in that the silicon controlled circuits for triggering are connected on the output stage of the triode N1 of ring detection/protective circuit in stealing line monitors interference circuit; The collection path of penetrating of multiple tube N3, N4 is serially connected in the path of controllable silicon G1; Optocoupler receiving tube NG1s is connected between the base stage and ground of multiple tube N3, N4; The biasing resistor R9 of triode N5 is serially connected in the path of controllable silicon G1; Light-emitting diode L1 and buzzer Beep and connect after be serially connected in triode N5 collection one penetrate on the path.

3. phone burglar alarm according to claim 1, the optocoupler receiving tube NG2s that it is characterized in that eavesdropping in the monitoring circuit is serially connected in the current supply circuit.

4. phone burglar alarm according to claim 1 is characterized in that thyristor gating circuit is connected between the control utmost point of power positive end and controllable silicon G1 in stealing line monitors interference circuit; Oscillating circuit is connected between power positive end and the silicon controlled anode; By optocoupler receiving tube NG1s, multiple tube N3, N4, the collection one emitter-base bandgap grading path of multiple tube N3, the N4 of this machine conversation anti-clutter circuit that resistance R 5, R20 form is connected in series with controllable silicon G1 path.