System and method for detecting three-way call attempts
Embodiments of this disclosure include methods in which a three-way call attempt is detected. Methods include monitoring the active communications of a telephone management system for pulses of energy indicative of a three-way call. A Fast Fourier Transform (FFT) is computed for each pulse of energy with time domain characteristics consistent with a click. Phases of each component for the pulse are also analyzed. If the phases are generally linear (i.e., if the phases have a common group delay or phase delay), then the pulse is a three-way call click and appropriate action (e.g., monitoring the call, terminating the call, warning the caller, etc.) is initiated.
1. A method, comprising:
monitoring an audio signal on a telephone line with a detector for a first period of silence, an energy pulse, and a second period of silence wherein the second period of silence follows the detection of the energy pulse;
processing the energy pulse wherein the energy pulse includes a plurality of frequency components;
determining a duration of the energy pulse on the telephone line;
calculating a phase for each of the plurality of frequency components to generate a plurality of phase values;
generating an alert signal when the plurality of phase values are linear and when the duration of the energy pulse is less than 40 milliseconds, wherein a three-way call attempt on the telephone line is identified by the alert signal; and
transmitting the alert signal to a host computer to identify the three-way call attempt on the telephone line.
2. The method of claim 1 , further comprising:
calculating a Fast Fourier Transform of the energy pulse to produce a complex coefficient for each of the plurality of frequency components.
3. The method of claim 1 , further comprising:
calculating a phase delay for each of the plurality of frequency components.
4. The method of claim 1 , further comprising:
calculating an unwrapped phase for each of the plurality of frequency components.
5. The method of claim 1 , further comprising:
calculating a group delay for each of the plurality of frequency components.
6. The method of claim 1 , wherein the duration of the energy pulse is approximately 40 milliseconds.
7. The method of claim 1 , further comprising:
monitoring the telephone line to detect the first period of silence, wherein the first period of silence has a duration lasting at least approximately 100 milliseconds.
8. The method of claim 1 , further comprising:
monitoring the telephone line to detect the second period of silence, wherein the second period of silence has a duration lasting at least approximately 100 milliseconds.
9. The method of claim 1 , wherein the first period of silence precedes the detecting of the energy pulse.
10. The method of claim 1 , wherein the energy pulse exceeds a predetermined amplitude.
11. The method of claim 1 , wherein an amplitude of the energy pulse has a value that exceeds a normalized silence audio level.
12. The method of claim 1 , further comprising:
monitoring a telephone call on the telephone line for the three-way call attempt.
13. The method of claim 1 , further comprising:
providing a prompt on the telephone line to warn a called party or a calling party that the three-way call attempt is detected.
14. The method of claim 1 , further comprising:
recording a telephone call on the telephone line when the three-way call attempt is detected.
15. The method of claim 1 , further comprising:
blocking a telephone call on the telephone line when the three-way call attempt is detected.
16. The method of claim 1 , further comprising:
blocking a future call to a telephone number associated with a called party via the telephone line when the three-way call attempt is detected.
17. The method of claim 1 , further comprising:
flagging a telephone call on the telephone line when the three-way call attempt is detected.
18. The method of claim 1 , further comprising:
disconnecting a telephone call on the telephone line when the three-way call attempt is detected.