Call classification overview

Last Updated : Dec 06, 2012 |
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Call classification, or call progress, is a method for determining who or what is on the other end of a call by analyzing the audio stream. When the analysis determines a probable match, the CCXML page receives a connection.signal event which contains the result in the event$.info.callprogress variable. Depending on the results of the analysis, call classification may continue for the duration of the call. In that case, the CCXML page will may receive multiple connection.signal events.
Call classification falls into two categories:
  • Tone-based classification. This category has a high degree of accuracy because it is easy for the system to detect busy signals or fax machine signals.
  • Speech-based classification. This category as a much lower degree of accuracy because it can be difficult to tell a human being's speech from an answering machine's recorded message.
Experience Portal uses speech-based classification when it detects an amount of energy in a frequency consistent with human speech. When it detects human speech, it differentiates between a live human being and an answering machine based on the length of the utterance. Generally, if a live human being answers, the utterance is relatively short while answering machine greetings are usually much longer.
For example, a live human might just say Hello. while an answering machine message might say Hello. I can't come to the phone right now. Please leave your message after the beep.
However, some people may answer the phone with a much longer greeting while others have recorded a very short answering machine greeting. In both of these cases, the call classification algorithm will incorrectly identify the call and assume the long greeting is a recorded message while the short greeting is a live human being.
To use call classification in your applications, make sure you design the application so that it takes such mistakes into account.
If you configure Experience Portal system to use H.323 connections and outcall applications, you must have Communication Manager with the SA8874 feature to detect that the call has been answered. Without the SA8874 feature, Experience Portal incorrectly detects that the call is answered even if the call is not answered.
If you configure Experience Portal system to use outcall applications, and want the Experience Portal system to differentiate human vs. answering machine, you require the Enhanced Call Classification license.