RU2761351C1 - Device for protection against unauthorized wiretapping talks in the indoor - Google Patents

Abstract

FIELD: protecting devices.SUBSTANCE: invention relates to a device for protecting against unauthorized wiretapping. The aforementioned technical result is achieved by the fact that the device for protection against unauthorized wiretapping in the room additionally contains a call signal generation unit and a phototransistor circuit-electronic switch, while the input of the call signal generation unit is connected to the output of the phototransistor circuit-electronic switch, the input of which is connected to the first the output of the power supply, the second output of which is connected to the first inputs of the switching unit and the control unit, while the output of the call signal generation unit is connected to the telephone set.EFFECT: increasing the efficiency of protecting speech information from leakage through technical channels, simplifying the device circuit.1 cl, 1 dwg

Description

The invention relates to devices for protection against unauthorized wiretapping in premises and protection against eavesdropping using devices using a telephone line as a line for transmitting intercepted information, or as a power source, or as a source of information about the state of the line for making a decision to turn on the wiretap mode.

A device is known for protecting a subscriber telephone set from unauthorized acoustic control [1].

The disadvantage of this device is that it does not have the ability to physically disconnect the telephone exchange line from the telephone set, which can lead to the selection of the nominal external voltage, which makes it possible to implement the channel of speech information leakage.

Known devices for the complex protection of the telephone line "Sprut" or "Proton", which implement the method, the essence of which is that in the intervals between conversations the telephone line is disconnected from the telephone set, which is guaranteed to prevent the signal "HF intrusion" from entering the telephone set [2] ...

These devices do not contain a description of the type of decoupling used, and the devices themselves include additional ringing devices, which are typical acoustoelectric transducers, that is, devices that contribute to the appearance of a "microphone effect" and conduct unauthorized acoustic control of the room.

Known device for protection against unauthorized wiretapping of conversations in a room in the intervals between telephone conversations, containing a unit for blocking unauthorized access devices and ensuring the operation of a regular telephone set, characterized in that the unit for blocking unauthorized access devices and ensuring the operation of a regular telephone set is made in the form of a remote executive unit installed outside the protected premises and containing a switching device connected to the incoming section of the telephone line, and connected to a control unit containing a control command allocation circuit and an electronic activity detector connected to it, connected to a standard telephone set [3]. The remote executive unit contains a rectifier, one input of which is connected through an isolating capacitor to the incoming section of the telephone line, while the output of the rectifier is connected to the winding of the polarized relay of the switching device, and the rectifier input is connected to one group of moving contacts of the polarized relay, which are connected to the incoming section of the telephone line , and the movable contacts of another group of polarized relay are connected to the input section and through a series-connected diode to isolate a pulse carrying information about switching on - positive polarity, a diode to isolate a pulse carrying information about reset - negative polarity, and both diodes are connected through the final protected section to the scheme of allocation of control commands of the control unit [3].

The device has significant disadvantages. The proposed scheme in the mode of calling the subscriber from the telephone set from the protected premises is not operational, since, being in the call standby mode, the unit, like the telephone itself, is de-energized. Thus, the subscriber picking up the handset to dial the number will do nothing.

The second disadvantage of the device proposed in the prototype is the ability of third parties to generate a false call signal, which will automatically connect the PBX line to the protected area and the telephone, and in order for the detector not to generate a shutdown pulse, along the circuit: input - key - protected area, - a “tube off” impulse is generated, the ringing voltage is removed and unauthorized listening to the protected premises is carried out.

The third drawback of the device proposed in the prototype is the possibility of third parties while listening to the conversations of subscribers on a given telephone line, after the end of the conversations of subscribers and lowering the handset on the levers of the telephone set along the chain: input - key - protected area - an impulse is formed that blocks the reset pulse, the line does not opens and the entire circuit becomes susceptible to high frequency intrusion.

A device for protection against unauthorized wiretapping in a room is known, containing an executive unit and a control unit, which are combined into a single protection unit connected to a telephone set, which contains an optical-electronic decoupling unit, the first input of which is connected to the input section of the telephone line, the second input connected to the power supply unit, which is connected, in turn, to the switching and control units, which are connected to each other, while the first output of the optoelectronic decoupling unit is connected to the call unit, and the second output of the optoelectronic decoupling unit through the movable contacts of the switching unit connected to the telephone set [4].

The device has the following disadvantage - when a call signal is received from a correspondent, the call signal is generated by a special unit, and not by the telephone set, which significantly limits the telephone set's capabilities for playing polyphonic melodies. At the same time, if you try to implement the expansion of the functions of the protection device for generating a call signal, this will lead to a significant increase in the device as a whole. In addition, in the case of using an electrodynamic loudspeaker as part of the call unit to reproduce the call signal, a device with a microphone effect appears in the call unit, which, even if the circuit is physically opened, will help to guide the information signal in the circuit leading to the automatic telephone exchange. This effect will be due to the compact arrangement of all units inside the protection device and the small distance between the conductors with the informative signal and the open circuit leading to the automatic telephone exchange. In this case, attackers will be able to use a low-noise signal amplifier and gain access to protected information.

The objective of the invention is to improve the efficiency of protection of speech information from leakage through technical channels, to simplify the circuit of the device, to maintain the ability to receive a call with a regular telephone set.

The problem is solved by the fact that in the device for protection against unauthorized wiretapping of conversations in the room, the executive unit and the control unit are combined into a single protection unit connected to a telephone set, which contains an optoelectronic decoupling unit, a switching unit and a control unit, characterized by the fact that that the protection unit additionally contains a block for generating a call signal and a phototransistor circuit - an electronic switch, while the input of the block for generating a call signal is connected to the output of the phototransistor circuit - an electronic switch, the input of which is connected to the first output of the power supply, the second output of which is connected to the first inputs of the switching unit and a control unit, while the output of the call signal generation unit is connected to a telephone set.

The proposed device provides for the preservation of the possibility of physically disconnecting the telephone from the automatic telephone exchange with the possibility of receiving a call ring at the moment when the handset of the telephone lies on the device and the circuit is physically open. In contrast to the prototype, in the proposed device it is proposed to replace the call generation unit with a call signal generation unit and to reduce the number of connections between the units.

The exclusion from the circuit of the call unit, which generates a call signal using an electrodynamic loudspeaker, will lead to the closure of the technical channel of the leakage of speech information, as well as to a decrease in the weight and dimensions of the protection device itself, since the generation unit is made in the form of a microcircuit.

Reducing the number of connections between blocks, in particular, reducing the number of outputs from the power supply, simplifies the production of the power supply and the circuit itself as a whole.

The essence of the invention is illustrated by drawings, where FIG. 1 shows a structural and functional diagram of a device consisting of:

1 - ATC;

2 - telephone set;

3 - protection block;

4 - block of optical-electronic decoupling;

5 - movable contacts;

6 - switching unit;

7 - power supply unit;

8 - control unit;

9 - light-emitting diode circuit for allocating a ringing tone;

10 - phototransistor circuit-electronic key;

11 - block for generating a call signal.

The device works as follows. In the initial state (Fig. 1), the telephone set 2 is disconnected from the automatic telephone exchange 1 through the normally open movable contacts 5 of the switching unit 6 in the absence of control voltage from the control unit 8.

In the absence of a call from PBX 1, the LED ringtone selection circuit 9 does not generate an optical signal to the phototransistor circuit-electronic switch 10, which, in the absence of an optical signal from the LED ringtone selection circuit, blocks the supply voltage to the call signal generation unit 11. The power supply 7 provides supplying the supply voltage to the control unit 8. The control unit 8 controls the electrical parameters of the telephone set 2 by measuring its electrical parameters at the moment when the handset of the telephone set lies on the device and at the moment when the receiver of the telephone set is lifted. The device is in standby mode.

When a call ring arrives from PBX 1 to the optoelectronic decoupling unit 4 of the protection unit 3, the LED ringtone isolation circuit 9 generates an optical signal to the phototransistor circuit-electronic key 10, which, at the moment of the presence of an optical signal from the LED ringtone isolation circuit 9, supplies the power supply voltage to the call signal generation unit 11, which generates a call signal similar to that coming from the PBX, while the signal received from the call signal generation unit 11 arrives at the telephone set 2 and the phone works normally, as when receiving a call signal from the PBX.

When deciding whether to answer an incoming call, the operator picks up the handset of the telephone set 1, thereby changing its electrical characteristics, while the control unit 8, which controls the state of the telephone set 1, generates a control voltage to the switching unit 6, which closes the moving contacts 5 of the circuit and connects PBX 1 to telephone set 2 and answers the incoming call. At the end of the conversation, the operator puts the receiver on the hook of the telephone set 2, thereby changing its electrical characteristics, while the control unit 8, which controls the state of the telephone set 1, removes the control voltage from the switching unit 6, which opens the moving contacts 5 of the circuit and disconnects the ATC 1 from telephone set 2.

If it is necessary to call the subscriber, the operator picks up the receiver of the telephone set 1, thereby changing its electrical characteristics, while the control unit 8, which controls the state of the telephone set 1, generates a control voltage to the switching unit 6, which closes the moving contacts 5 of the circuit and connects the ATC 1 to the telephone set 2, and the operator, having dialed the subscriber's number, when the call is answered, talks to him.

At the end of the conversation, the operator puts the receiver on the hook of the telephone set 2, thereby changing its electrical characteristics, while the control unit 8, which controls the state of the telephone set 1, removes the control voltage from the switching unit 6, which opens the moving contacts 5 of the circuit and disconnects the ATC 1 from telephone set 2.

Considering the fact that the input of the telephone set receives a signal similar to the call signal from the PBX, the telephone set reproduces the standard call signal set by the user, while there is no need to adapt to the new call signal or to upgrade the protection device, which, as a result, will lead to it. rise in price.

Thanks to the proposed invention, not only an increase in the efficiency of protection of speech information is provided, but also the normal operation of the telephone itself in the mode of receiving a call from a PBX, eliminating the need to create an additional call device, which helps to reduce the weight and dimensions of the protection device and simplify its production.

A comparative analysis of the essential features of the prototype and the proposed invention shows that the claimed invention, due to the inclusion of the signal generator and the phototransistor circuit in the protection unit, is an electronic key so that the input of the call signal generation unit is connected to the output of the phototransistor circuit is an electronic key, the input of which connected to the first output of the power supply, the second output of which is connected to the first inputs of the switching unit and the control unit, while the output of the call signal generation unit is connected to the telephone set, it allows to obtain a technical result consisting in increasing the efficiency of protecting speech information from leakage through technical channels, simplification of the device circuit, preserving the possibility of receiving a call with a regular telephone set, which was impossible in the prototype.

SOURCES OF INFORMATION

1. RF patent No. 2350032.

2. Passports of products "Proton" or "Sprut", "Electronic device for complex protection of the telephone line" JSC "Radius", Leninsky Prospect, 41/2 tel. 135-33-94, Moscow.

3. RF patent No. 2145153.

4. RF patent No. 2632188 - prototype.

Claims (1)

A device for protecting against unauthorized wiretapping in a room, the executive unit and the control unit of which are combined into a single protection unit connected to the telephone set, which contains an optoelectronic decoupling unit, a switching unit and a control unit, characterized in that the protection unit additionally contains a unit generating a call signal and a phototransistor circuit - an electronic switch, while the input of the call signal generation unit is connected to the output of the phototransistor circuit - an electronic switch, the input of which is connected to the first output of the power supply, the second output of which is connected to the first inputs of the switching unit and the control unit, while the output of the call signal generation unit is connected to the telephone set.

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