RU2632188C1 - Device for protection against unauthorized listening of conversations in room - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: in the device for protecting against unauthorized listening of conversations in a room comprising an execution unit and a control unit, according to the invention, the executive unit and the control unit are combined into a single protection unit connected to a telephone unit which contains a unit of optical-electronic isolation, a first input of which is connected to the input section of the telephone line, a second input is connected to a power supply unit which is connected in turn to switching and control units which are connected to each other, the first output of the optical-electronic isolation unit is connected to a call unit, and the second output of the optical-electronic isolation unit is connected to the telephone set through the movable contacts of a switching unit. The replacement of a mechanical connection unit of the circuit by the optical-electronic isolation unit connected to the call unit, and adding the power supply units, the control and switching allows the operator to initiate manual mode of mechanical connection and disconnection of the central office line to the telephone set by lifting and lowering the handset of the telephone set.

EFFECT: increased efficiency of voice information protection against leakage through technical channels.

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Description

The invention relates to devices for protecting against unauthorized listening to conversations in rooms and for protecting 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 a line for deciding whether to enable listening mode.

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

The disadvantage of this device is that it does not have the ability to physically open the telephone line of the telephone exchange from the telephone, which in turn can lead to the selection of the external voltage rating, which makes it possible to implement a voice leak channel.

Known devices for comprehensive protection of the telephone line "Octopus" or "Proton" that implement the method, the essence of which is that in the intervals between negotiations the telephone line is disconnected from the telephone, which is guaranteed to prevent the signal "HF imposition" on the telephone [2] .

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

A device is known for protecting against unauthorized listening to conversations in a room between telephone calls, comprising a unit for blocking devices of unauthorized access and ensuring the operation of a regular telephone set, characterized in that the blocking device for unauthorized access and ensuring the operation of a standard telephone set is made in the form of a remote executive unit installed outside the protected room 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 isolation capacitor to the incoming section of the telephone line, while the output of the rectifier is connected to the coil of the polarized relay of the switching device, and the input of the rectifier is connected to one group of movable contacts of the polarized relay that are connected to the incoming section of the telephone line , and the movable contacts of another group of polarized relays are connected to the incoming section and through a series-connected diode to isolate the impu bca carrying information about turning - positive polarity, a diode for isolating pulse indicative of the discharge - of negative polarity, the two diodes via the end portion connected to the protected circuit selection control command of the control unit [3].

The device has significant disadvantages. The proposed scheme in the mode of calling a subscriber from a telephone set from a protected room is not operational, since, being in the standby mode of a call, the unit, like the telephone set itself, is de-energized. Thus, a subscriber picking up a phone to dial a number will not lead to anything.

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

The third disadvantage of the device proposed in the prototype is the possibility of third parties during listening to subscribers ’conversations on a given telephone line, after completing subscribers’ conversations and lowering the handset to the levers of the telephone set through a circuit: input — key — protected section generates an impulse blocking the reset impulse; and the whole chain becomes subject to high-frequency imposition.

The objective of the invention is to increase the efficiency of protection of voice information from leakage through technical channels, as well as simplifying the production, installation and operation of such devices.

The problem is solved in that in the device for protection against unauthorized listening to conversations in a room containing an executive unit and a control unit, according to the invention, the executive unit and the control unit are combined into a single protection unit connected to a telephone, which contains an optical-electronic isolation unit, the first input of which is connected to the input section of the telephone line, the second input is connected to a power supply unit, which, in turn, is connected to switching and control units, which are interconnected, while the first output of the optoelectronic isolation unit is connected to the call unit, and the second output of the optoelectronic isolation unit is connected to the telephone through the movable contacts of the switching unit.

Due to the mechanical rupture of the line section in the protected room at a time when the line is not used for telephone conversations with manual reconnection when ringing signals are received from the telephone exchange and manual re-breaking of the line after the end of the communication session, the telephone line is highly protected from information leaks, which is a source of danger of unauthorized listening to conversations indoors. Thanks to the invention, not only the protection of voice information is ensured, but also the normal operation of the telephone itself, ease of installation and operation of such devices.

In addition, the small passage capacity of the open movable contacts of the switching unit makes it impossible to listen to the room using devices using the high-frequency (RF) imposition method, since the amplitude of the RF signals penetrating the telephone set is negligibly small and insufficient for the normal operation of these devices, and therefore there is no need to use additional protection devices from RF imposition.

Replacing the mechanical connection unit of the circuit with an optoelectronic isolation unit connected to the call unit and adding power, control and switching units allows the operator to initiate a manual mode of mechanical connection and disconnection of the telephone exchange line by lifting and lowering the telephone handset, however, such a replacement does the device is slightly more expensive.

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

1 - automatic telephone exchange;

2 - telephone;

3 - protection unit;

4 - block optical-electronic isolation;

5 - call block;

6 - movable contacts;

7 - switching unit;

8 - power supply;

9 - control unit;

10 - LED circuit allocation call;

11 is a phototransistor circuit for highlighting a call.

The device operates as follows. In the initial state shown in FIG. 1, the telephone 2 is disconnected from the PBX 1 through normally open moving contacts 6 of the switching unit 7 in the absence of control voltage from the control unit 9.

In the absence of a call from the PBX 1, the LED circuit for allocating a call 10 does not generate an optical signal for the phototransistor circuit for allocating a call 11, which blocks the supply of voltage to the electromechanical transducer — a bell (not shown in FIG. 1) call block 5. The power supply 8 provides a supply voltage to the control unit 9. The control unit 9 controls the electrical parameters of the telephone 2 by measuring its electrical parameters at the time when the handset of the telephone is on the device, and at the time when the telephone is picked up. The device is in standby mode.

Upon receipt of a call from the PBX 1 to the optoelectronic isolation unit 4 of the protection unit 3, the LED circuit for allocating the call 10 generates an optical signal for the phototransistor circuit for isolating the call 11, which, at the time of the presence of the optical signal from the LED circuit for isolating the call 10, provides voltage to the electromechanical transducer - the bell (not shown in Fig. 1) of the call block 5 and the electromechanical transducer - the bell emits acoustic vibrations available to the operator .

When deciding whether to answer an incoming call, the operator picks up the telephone 1, thereby changing its electrical characteristics, while the control unit 9, which controls the state of the telephone 1, generates a control voltage to the switching unit 7, which closes the movable contacts 6 of the circuit and connects the PBX 1 to the telephone 2 and answers the incoming call. At the end of the conversation, the operator places the receiver on the levers of the telephone 2, thereby changing its electrical characteristics, while the control unit 9, which controls the state of the telephone 1, removes control voltage from the switching unit 7, which opens the movable contacts 6 of the circuit and disconnects the PBX 1 from telephone set 2.

If it is necessary to call the subscriber, the operator picks up the telephone receiver 1, thereby changing its electrical characteristics, while the control unit 9, which controls the state of the telephone 1, generates a control voltage to the switching unit 7, which closes the movable contacts 6 of the circuit and connects the PBX 1 to the telephone apparatus 2, and the operator, having dialed the subscriber’s number when receiving a call, speaks with him.

At the end of the conversation, the operator places the receiver on the levers of the telephone 2, thereby changing its electrical characteristics, while the control unit 9, which controls the state of the telephone 1, removes control voltage from the switching unit 7, which opens the movable contacts 6 of the circuit and disconnects the PBX 1 from telephone set 2.

A comparative analysis of the essential features of the prototype and the present invention shows that the claimed invention, by manually controlling the mechanical disconnection of the telephone from the rest of the telephone line of the telephone exchange, combining the executive unit and the control unit into a single protection unit containing an optoelectronic isolation unit, one input of which is connected with the incoming section of the telephone line, the second input is connected to a power supply, which is connected to the switching and control units, which are interconnected, and the control unit is connected to the telephone to monitor the state of its electrical parameters, while one output of the optoelectronic isolation unit is connected to the call unit, and the second output of the optoelectronic isolation unit is connected to the telephone through the movable contacts of the switching unit, which allows to obtain a technical result consisting in increasing the efficiency of protection of voice information from leakage through technical channels, as well as simplifying the production, installation and operation of such devices, which was impossible It is possible in the prototype.

INFORMATION SOURCES

1. RF patent 2350032 - analogue.

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

3. RF patent 2145153 - prototype.

Claims (1)

A device for protecting against unauthorized listening to conversations in a room, comprising an executive unit and a control unit, characterized in that the executive unit and the control unit are combined into a single protection unit connected to a telephone, which contains an optical-electronic isolation unit, the first input of which is connected to the input section of the telephone line, the second input is connected to a power supply unit, which, in turn, is connected to switching and control units that are interconnected, while the first the progress of the optoelectronic isolation unit is connected to the call unit, and the second output of the optoelectronic isolation unit is connected to the telephone through the movable contacts of the switching unit.

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