Three way call detection

A system for detecting three way call attempts comprising:

• a digital signal processor having a pair of inputs for receiving audio signals from remote and local signal sources;
• and
• a memory associated with the digital signal processor;
• and
• an audio signal analysis program stored in the memory for detecting indicia of three way call events among the audio signals, the signal analysis program comprising:
• a sampling engine for generating a sorted profile of audio signal levels from the audio signals received by the digital signal processor;
• and
• a comparison engine coupled to the sampling engine for monitoring the profile of audio signals with reset and reference conditions, resetting the profile when a reset condition is detected, and providing an output indication of a three way call event when a reference condition is detected and no reset condition is detected during a first interval.

A system for detecting three way call attempts comprising:

• a digital signal processor having a pair of inputs for receiving audio signals from remote and local signal sources;
• a memory associated with the digital signal processor;
• an audio signal analysis program stored in the memory for detecting indicia of three way call events among the audio signals, the signal analysis program comprising:
• a sampling engine for generating a profile of audio signal levels from the audio signals received by the digital signal processor;
• a comparison engine coupled to the sampling engine for monitoring the profile of audio signals with reset and reference conditions, resetting the profile when a reset condition is detected, and providing an output indication of a three way call event when a reference condition is detected and no reset condition is detected during a first interval;
• and
• a signal origin discrimination engine coupled to the digital signal processor and the sampling and comparison engines for adjusting the levels of sampled audio signals according to levels of audio signals detected on a local telephone line, comparing the adjusted signal levels with a reference threshold level to determine whether sampled signals originate on the telephone line, and providing an indication of the origin of the sampled signals to the comparison engine.

A computer readable storage medium on which data is stored 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 from a telephone line;
• sorting the sampled audio signals according to a a level associated with each sampled signal to produce a profile of sorted signals;
• monitoring the profile of sampled signals for reference and reset conditions;
• resetting the profile when a reset condition is detected;
• and
• tagging the profile as a potential click when no reset conditions are detected for a first preselected interval and a reference condition is detected.

A method for detecting three way call attempts on a telephone line, the method comprising the steps of;

• initializing a sample counter and profile counters to track a number of times an audio signal is sampled and levels associated with the samples of the audio signal, respectively;
• sampling the audio signal in a sample window;
• sorting the sampled audio signals in the sample window according to a signal level associated with each sampled signal;
• adjusting the profile counters according to the level associated with each sampled audio signal;
• monitoring the adjusted profile counters for reset and reference conditions;
• returning to the initializing step when a reset condition is detected;
• returning to the sampling step when no reset condition is detected and the sample counter does not equal a reference value;
• and
• tagging the sample window as a potential three way call event when no reset condition is detected, a reference condition is detected, and the sample counter equals the reference value.