Method and apparatus for telephone call fraud detection and prevention

• US 6,914,968 B1
• Filed: 07/28/2000
• Issued: 07/05/2005
• Est. Priority Date: 08/05/1999
• Status: Active Grant

• Current Assignee: VTech Telecommunications Limited (VTech Holdings Ltd.)
• Original Assignee: VTech Telecommunications Limited (VTech Holdings Ltd.)
• Inventors: McCullough, Sheldon Dean, Ryley, Gordon Bradley
• Primary Examiner(s): Bui, Bing Q.
• Application Number:
  US09/628,147
• Time in Patent Office: 1,803 Days
• Field of Search: 379/7, 379/22.03, 379/29.08, 379/114.14, 379/127.02, 379/140, 379/145, 379/155, 379/188, 379/189, 379/194, 379/195, 379/200, 379/399.01, 379/32.01, 379/32.04, 379/35, 379/199
• US Class Current: 379/188
• CPC Class Codes: H04M 1/67 by electronic means

Abstract

The present disclosure discloses a method and apparatus for detecting and preventing telephone call fraud. The call fraud detector apparatus is connected to the telephone line, and includes a telephone line interface with switch hook. A parallel set detector indicates to the microcontroller that another device has gone off hook on the telephone line. The microcontroller causes the telephone line interface switch hook to also go off hook in parallel, thereby preventing pulse dialing by the other device. The device may also include a DTMF tone detector and generator to prevent DTMF dialing on the telephone line. The call fraud detector can provide a visual, audible, and/or tactile indication when unauthorized use of the telephone line occurs, and can be enabled or disabled by an external device. The call fraud detector can log the time and date of each unauthorized call placed on a line, and can also notify the telephone service provider when an unauthorized call is attempted.

Claims

1. A method for preventing telephone calls from being initiated using a current loop wire line telephone connection, which method comprises:

connecting a device incorporating a switch hook to a telephone line;

detecting the use of the telephone line, by a telecommunication apparatus connected to the telephone line;

activating the switch hook of the device to go off hook;

detecting one or more Dual Tone Multi-Frequency signals on the telephone line;

generating a constant Dual Tone Multi-Frequency signal in response to detecting one or more Dual Tone Multi-Frequency signals;

applying the constant Dual Tone Multi-Frequency signal to the telephone line, whereby Dual Tone Multi-Frequency dialing cannot take place on the telephone line, and

notifying the telephone company that an unauthorized call is in progress,

the step of notifying the telephone company comprised of the substep of applying by the device a predetermined multi-frequency signal to the telephone line, whereby the device can utilize the extended Dual Tone Multi-Frequency signaling set to notify the telephone company that an unauthorized call is in progress, and whereby the telecommunication apparatus is unable to place an outgoing call using the telephone line.

2. The method of claim 1, further comprising enabling a security switch that can be enabled or disabled, wherein when the security switch is enabled, the switch hook is activated to go off hook during use of the telephone line by a telecommunications apparatus connected thereto.

3. The method of claim 2, in which the switch hook is enabled and/or disabled at predetermined times by an external circuit.

4. The method of claim 3, in which the external circuit is a property security system.

5. The method of claim 1, in which the step of detecting one or more Dual Tone Multi-Frequency signals comprises the substep of detecting a predetermined sequence of Dual Tone Multi-Frequency signals.

6. The method of claim 5, in which the predetermined sequence of Dual Tone Multi-Frequency signals is programmable.

7. The method of claim 1, further including the subsequent step of recording the time and date corresponding to each detected unauthorized use of the telephone line, whereby a record of attempted calls is made.

8. A method for preventing telephone calls from being initiated using a current loop wire line telephone connection which method comprises:

connecting a device incorporating a switch hook to a telephone line;

detecting the use of the telephone line, by a telecommunication apparatus connected to the telephone line;

activating the switch hook of the device to go off hook;

detecting one or more Dual Tone Multi-Frequency signals on the telephone line;

generating a constant Dual Tone Multi-Frequency signal in response to detecting one or more Dual Tone Multi-Frequency signals;

applying the constant Dual Tone Multi-Frequency signal to the telephone line, whereby Dual Tone Multi-Frequency dialing cannot take place on the telephone line, and

notifying the telephone company that an unauthorized call is in progress,

the step of notifying the telephone company comprised of the substep of

initiating a digital communications link with the telephone company, and

transmitting data indicating the occurrence of one or more unauthorized call attempts.

9. A method for preventing telephone calls from being initiated using a current loop wire line telephone connection, which method comprises:

connecting a monitor device incorporating a switch hook to a telephone line;

detecting the use of the telephone line, by a telecommunication apparatus connected to the telephone line;

activating the switch hook of the device to go off hook;

detecting one or more Dual Tone Multi-Frequency signals on the telephone line;

generating a constant Dual Tone Multi-Frequency signal in response to detecting one or more Dual Tone Multi-Frequency signals;

applying the constant Dual Tone Multi-Frequency signal to the telephone line, whereby Dual Tone Multi-Frequency dialing cannot take place on the telephone line, and

notifying the telephone company that an unauthorized call is in progress,

the step of notifying the telephone company comprised of the substep of

initiating a digital communications link with the telephone company; and

transmitting data indicating the occurrence of one or more unauthorized call attempts, in which the step of transmitting data indicating the occurrence of one or more unauthorized call attempts further includes the substep of transmitting data indicating the time and date of the unauthorized call attempts.

10. The method of claim 9, wherein the monitor device comprises:

a telephone line interface for connection to a telephone network line, in which the switch hook alternatively places the device in an on-hook or off-hook position, whereby the telecommunication apparatus operatively connected to the telephone network line is unable to place an outgoing call using the telephone network line when the device is in an off-hook position;

a line monitor circuit connected to the telephone line interface, which circuit provides an output signal when a telephone device operatively connected to the telephone line has gone off hook; and

a microcontroller circuit electrically connected to the parallel set detection circuit output, the microcontroller providing an output which controls the state of the hook switch.

11. The method of claim 10, wherein the monitor device further includes a security switch, which switch enables and disables operation of the switch hook, the switch being electrically connected to the microcontroller circuit.

13. The method of claim 10, wherein the monitor device further includes a clock circuit electrically connected to the microcontroller circuit.

12. The method dee of claim l0, wherein the monitor device further includes a Dual Tone Multi-Frequency signal detector with an input electrically connected to the telephone line, and output electrically connected to the microcontroller circuit, whereby the Dual Tone Multi-Frequency detector outputs decoded Dual Tone Multi-Frequency signals to the microcontroller.

14. The method of claim 12, wherein the monitor device further includes a Dual Tone Multi-Frequency signal generator, having an input electrically connected to the microcontroller circuit, and which output is electrically connected to the telephone line.

15. The method of claim 12, wherein the monitor device further includes a telephone line data modem connected to the microcontroller circuit, and also connected to the telephone line, whereby the modem provides for digital communications between the microcontroller and the telephone network.

16. The method of claim 12, wherein the monitor device further includes a wireless RF transceiver connected to the microcontroller circuit, whereby the transceiver provides for communications indicating unauthorized call activity between the microcontroller and a wireless communications network.

17. The method of claim 12, wherein the monitor device further includes an indicating means, electrically-connected to the microcontroller circuit, whereby the indicating means provides indication to the device user of whether the telephone line is being used.