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Call Progress Analysis (CPA)

Ensure your outbound messages are heard

Reliable & Highly Accurate

Leverages the strength of our Speech Recognizer by constantly listening for various tones, just as it would when performing speech recognition.

Professional Delivery

Your outbound dialing application sounds more professional because it will start precisely where it should; as soon as a voicemail beep is detected.


Fully supported through the standards-based Media Resource Control Protocol (MRCP) and compatible with most voice platforms and PBX systems.

Tone-Based Detection Gets Your Message Heard with Over 98% Accuracy

LumenVox’ new Call Progress Analysis (CPA) increases the effectiveness of your outbound messaging application. Built on, and replacing, our Answering Machine Detection (AMD) technology, this new solution increases its reach beyond detecting answering machine and voicemail tones.

It now analyzes the audio during call startup, scanning for telephony messaging tones. When the call is connected, it automatically begins to listen for fax or voicemail tones. With it, you can rest assured that your predictive dialer or IVR is getting the right message to the desired recipient more accurately than ever.

*98% is measured in large scale testing, based on recordings of actual calls. Accuracy may vary.

A Unique Approach

Our tone-based detection represents a significant innovation compared to many other energy-based answering machine detection technologies. Most systems guess whether the call is connected to a human based on energy levels and timing queues, resulting in unacceptably inaccurate messaging applications.

Available in the LumenVox Speech Recognizer, Call Progress Analysis is an effective method of verifying that an outbound call has been connected to a live person or an automated recording system.

Voice Mail is Detected

Message restarts at the beginning or a custom voice mail message is played.

Human is Detected

Message begins playing at the beginning of the call.

How Call Progress Analysis Works



Leverages the strength of our Speech Recognizer by constantly listening for various tones, just as it would when performing speech recognition. 


Audio is compared to special acoustic models for matches, similar to our ASR’s function.


Message is played at the appropriate time.

Learn More

Looking for more specific information about the LumenVox Call Progress Analysis (CPA)? Click for: a complete list of featurestechnical specifications; or additional documentation.

Still have questions? We’d be happy to help, just contact us via the form below.

Experience Call Progress Analysis. Schedule a Demo Today.

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