GB2068682A

GB2068682A - Telephone eavesdropper detector

Info

Publication number: GB2068682A
Application number: GB7942072A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-12-06
Filing date: 1979-12-06
Publication date: 1981-08-12

Abstract

D.C. telephone line voltage is fed via a polarity protection device A and a balancing control B to a comparator C for comparison with a reference voltage provided at D. Any imbalance between the compared voltages caused by the connection of another telephone to the like will produce an indication at E. <IMAGE>

Description

SPECIFICATION Telephone eavesdropper detector The "Telephone Eavesdropper Detector" is a unit that may be attached to the telephone or any section of the line, and indicates the following information; If someone is listening on an extension phone, If any listening device has been attached to the line, or If someone else is using your line or extension.

The unit consists of a circuit housed within a small box. It's external features consist of two controls that are for the adjustment of the balance ofthe current, one of which is a fine tuning adjustment that makes the unit more sensitive to slight current variation.

Two leads go from the unit to the telephone system.

An indicator light and/or meter gives a visible indication if any of the states described in the above paragraph exist. The unit also has an on/off switch. The circuit can be mounted on a surface as small as f" x 2" and comprises as the attached logic circuit shows of: (A) An input and polarity protection device against incorrect wiring or reversal of polarity. (B) Which is a balancing control for the information fed from the telephone line. (C) The comparator which compares the current from the line and the reference source. (D) The reference source. (E) The indicator which gives a visible indication of any imbalance between the reference source and the input at (A) above. In fact, the current is fed from the line through (A) and made stable by (B) before it is fed into the comparator at (C).Also (D) is fed into the comparator and any imbalance is assessed by (C) and indicated through (E). The advantage of this unit is that it is small and discreet, inexpensive to pro duce but has a wide range of application described above.

CLAIM

The telephone eavesdropper detector is a device that will detect any on line tap that has been connected to the telephone or or any part of the consumers telephone equipment, for example the junction box or any point on the line.

The device will indicate by the lighting up of an L.E.D. (Light emitting diode) any of the following conditions. (A) When the telephone handset has been picked up, if there is any listening device such as a 'bug' on the line, connected in either series or parallel across the line. (B) If any person is listening on another extension or listening to the call from the switchboard complex. (D) By readjusting the unit, it will light up if the telephone handset is down on the hook and someone initiates an infinity device which allows the phone to function as an eavesdropper.

The above are the claims I make in respect of my invention.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

SPECIFICATION Telephone eavesdropper detector The "Telephone Eavesdropper Detector" is a unit that may be attached to the telephone or any section of the line, and indicates the following information; If someone is listening on an extension phone, If any listening device has been attached to the line, or If someone else is using your line or extension.

The unit consists of a circuit housed within a small box. It's external features consist of two controls that are for the adjustment of the balance ofthe current, one of which is a fine tuning adjustment that makes the unit more sensitive to slight current variation.

Two leads go from the unit to the telephone system.

An indicator light and/or meter gives a visible indication if any of the states described in the above paragraph exist. The unit also has an on/off switch. The circuit can be mounted on a surface as small as f" x 2" and comprises as the attached logic circuit shows of: (A) An input and polarity protection device against incorrect wiring or reversal of polarity. (B) Which is a balancing control for the information fed from the telephone line. (C) The comparator which compares the current from the line and the reference source. (D) The reference source. (E) The indicator which gives a visible indication of any imbalance between the reference source and the input at (A) above. In fact, the current is fed from the line through (A) and made stable by (B) before it is fed into the comparator at (C).Also (D) is fed into the comparator and any imbalance is assessed by (C) and indicated through (E). The advantage of this unit is that it is small and discreet, inexpensive to pro duce but has a wide range of application described above.

CLAIM

The telephone eavesdropper detector is a device that will detect any on line tap that has been connected to the telephone or or any part of the consumers telephone equipment, for example the junction box or any point on the line.

The device will indicate by the lighting up of an L.E.D. (Light emitting diode) any of the following conditions. (A) When the telephone handset has been picked up, if there is any listening device such as a 'bug' on the line, connected in either series or parallel across the line. (B) If any person is listening on another extension or listening to the call from the switchboard complex. (D) By readjusting the unit, it will light up if the telephone handset is down on the hook and someone initiates an infinity device which allows the phone to function as an eavesdropper.

The above are the claims I make in respect of my invention.