US5805685A — Three way call detection by counting signal chara…

Claim 1

Independent Claim 104 words

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.

Claim 2

Independent Claim 104 words

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.

Claim 3

Dependent Claim 41 words

The method of claim 1, wherein the monitoring step comprises the substeps of: comparing the high, low, and no-signal counters with associated threshold levels; and resetting the high, low, and no-signal counters when any of the associated threshold levels are reached.

Claim 4

Dependent Claim 45 words

The method of claim 1 comprising the additional steps of: responsive to the flag being set, resetting the high, low, and no-signal counters; repeating the sampling, incrementing, monitoring and testing steps; and indicating a click event when the preselected value is reached a second time.

Claim 5

Dependent Claim 51 words

The method of claim 3, comprising the additional steps of: following the indicating step, sampling audio signals for an additional period to determine whether the telephone line is silent; and responsive to a determination that the telephone line is silent, generating an indication that a three way call attempt has occurred.

Claim 6

Dependent Claim 78 words

The method of claim 1, wherein the incrementing step comprises the substeps of: determining an absolute value of the sampled signal; incrementing the high signal counter when the absolute value is at least as large as a first value; incrementing the low signal counter when the absolute value is at least as large as a second value and less than the first value; and incrementing the no-signal counter when the absolute value is less than the second value.

Claim 7

Dependent Claim 66 words

The method of claim 1, comprising the additional steps of: adjusting each sampled signal to correct for sidetones and hysteresis; incrementing a first counter when the adjusted signal exceeds a reference threshold and incrementing a second counter otherwise; and providing an indication that the sampled signals originate on the telephone line when the first counter exceeds a value characteristic of audio signals on the telephone line.

Claim 8

Independent Claim 152 words

A system for detecting three way call attempts comprising: 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.

Claim 9

Independent Claim 152 words

A system for detecting three way call attempts comprising: 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.

Claim 10

Dependent Claim 73 words

The system of claim 7, wherein the audio signal analysis program further comprises a signal origin discrimination engine coupled to the digital signal processor and the sampling engine for adjusting the levels of sampled audio signals according to levels of audio signals detected on a second telephone line, comparing the adjusted signal levels with a reference threshold level and providing an indication of the origin of the sampled signals based on the comparison.

Claim 11

Dependent Claim 34 words

The system of claim 8, wherein the signal origin discrimination engine includes a counter which is incremented when adjusted signal levels fall below the reference threshold, for measuring sampled audio signals for silence intervals.

Claim 12

Dependent Claim 131 words

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: 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.

Claim 13

Dependent Claim 131 words

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: 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.

Claim 14

Independent Claim 120 words

A method for sampling audio signals from a telephone line to detect three way call attempts, the method comprising: 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.

Claim 15

Independent Claim 120 words

A method for sampling audio signals from a telephone line to detect three way call attempts, the method comprising: 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.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-09-07	2002-03-09	2002-09-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-09-07	2006-03-09	2006-09-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-09-07	2010-03-09	2010-09-08	$7700.00	Window Closed / Lapsed

Three way call detection by counting signal characteristics

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