Call-Progress Analysis…Some Science, Plenty of Art
Every time we place a call, we instinctively perform call-progress analysis (CPA). We listen for dial tone before dialing, detect ring back, busy, answer, and so on, without giving it much thought. But duplicating the nearly unfailing precision of human-based CPA in a multiline communications system requires considerable technical accomplishment and even more experience and inventiveness.
Most of you know that CPA is essential for outbound PSTN calls, but it’s also necessary in SIP-based systems, since, once a SIP call is answered, there is no more SIP signaling, a SIP system still must have in-band CPA to classify the answer. Is it a voice answer or SIT (system intercept tone)? How about CED, the fax-answer tone? And, in outbound call-center applications, it’s critically important to know whether voice answer is a person or an answering machine. The difference between a less-than-effective answering-machine detection in CPA and one that achieves better than 90% accuracy, such as Commetrex’ CPA, can mean a savings of over $100,000 per year in a moderate-sized call center.
There is plenty of debate over how to best detect answering machines. Some systems rely on beep tones, but they are unreliable and of indeterminate frequency. And there is no spectral signature of answering machines. So, what to do? Well, the answer lies in Commetrex’ 10 years-in-the-field CPA.
Our CPA uses frequency analysis to discriminate between voice, which has frequencies throughout the PSTN bandwidth, and CPA tones, which are between 200 and 500 Hertz. But once we determine that there is voice answer, is it a machine?
The answer lies in the differences between how we answer a call in person, and the type of message we record for our home systems. Have you ever heard an answering machine just say, “Hello”?
Commetrex’ CPA gives you the features that allow you to differentiate between “Hello” and “Hi, this is Ted and Alice. We’re not in just now, but…” You can license this highly effective CPA, which is used on BladeWare, for your telecom equipment. Many have and you can too. But now it’s finally in BladeWare 3.0.
Want to know more? E-mail us at firstname.lastname@example.org.