Three way call detection by counting signal characteristics
First Claim
1. A method for sampling audio signals from a telephone line to detect three way call attempts, the method comprising the steps of:
- sampling audio signals on the telephone line at a selected sampling rate;
incrementing high, low or no-signal counters according to an amplitude measured for each sampled signal;
monitoring the high, low, and no-signal counters for a reset condition;
testing the high, low, and no signal counters for a reference condition when a sum of the high, low, and no signal counters reaches a preselected value; and
setting a flag when the reference condition is detected and the reset condition is not detected.
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Accused Products
Abstract
A system and method for analyzing audio signals sampled from a telephone line during moving sample windows in order to detect indicia of three way calling attempts. The system and method sample audio signals on the telephone line, sort the sampled signals into a profile of levels for the sampled audio signals, and monitor the profile of sampled audio signals for reset and reference conditions. Reset conditions are pulse patterns identified from sampled audio signals that are inconsistent with patterns generated by three way call events. Reference conditions are pulse patterns identified from sampled audio signals that are consistent with patterns generated by three way call events. A sampling window and its associated profile are reset when reset conditions are detected. The profile is tagged as a potential three way call event when reference conditions are detected in a sample profile and no reset conditions are detected over the selected sampling interval (sampling window). In the preferred embodiment, an indication that a three way call attempt is occurring is generated when two consecutive tagged profiles are detected.
181 Citations
11 Claims
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1. A method for sampling audio signals from a telephone line to detect three way call attempts, the method comprising the steps of:
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sampling audio signals on the telephone line at a selected sampling rate; incrementing high, low or no-signal counters according to an amplitude measured for each sampled signal; monitoring the high, low, and no-signal counters for a reset condition; testing the high, low, and no signal counters for a reference condition when a sum of the high, low, and no signal counters reaches a preselected value; and setting a flag when the reference condition is detected and the reset condition is not detected. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for detecting three way call attempts comprising:
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a digital signal processor having an input for receiving audio signals from a first telephone line; a memory associated with the digital signal processor; and an audio signal analysis program stored in the memory for detecting indicia of a three way call event in the audio signal, the signal analysis program comprising; a sampling engine, including a plurality of counters, for sampling the audio signal and adjusting the counters according to the amplitude of the sampled signal relative to first and second signal levels; and a comparison engine coupled to the sampling engine to monitor the plurality of counters for a reset condition, sum the plurality of counters, test the plurality of counters for a reference condition when the sum exceeds a preselected value, and indicate a click event has occurred when a reference condition is detected and no reset condition is detected. - View Dependent Claims (8, 9)
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10. A computer readable storage medium on which is stored data for analyzing audio signals provided to a digital signal processor, the digital signal processor implementing the data to perform a process comprising the steps of:
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sampling the audio signals at a selected sampling rate; incrementing at least one of a plurality of signal amplitude counters according to an amplitude measured for each sampled signal to determine a profile of sampled signals, each signal amplitude counter associated with a different threshold signal amplitude; summing the plurality of signal amplitude counters to determine a count of signal amplitudes in the profile; monitoring the profile for a reset condition; and tagging the profile as a potential click when the count of the signal amplitudes reaches a preselected level and a reference condition is detected.
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11. A method for sampling audio signals from a telephone line to detect three way call attempts, the method comprising:
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sampling audio signals on the telephone line at a selected sampling rate; incrementing at least one of a plurality of signal amplitude counters according to an amplitude measured for each sampled signal, each signal amplitude counter associated with a different threshold signal amplitude; summing the plurality of signal amplitude counters to determine a count of signal amplitudes in the profile; monitoring the count of the signal amplitudes for a reset condition; testing any of the plurality of signal amplitude counters for a reference condition; and setting a flag when the reference condition is detected and the reset condition is not detected.
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Specification