Software guessing whether a human or a voicemail picked up. Useful, genuinely imperfect, and worth understanding before you rely on it.
It listens to the first couple of seconds. A human says hello and stops. A voicemail greeting runs on, has a beep, and often starts with a recorded name.
From that the system decides. It is a probability judgement made in about two seconds, not a fact.
Both failure modes cost you something, and tuning to avoid one gives you more of the other.
Detection makes a power dialler bearable at volume. It also means some proportion of people who picked up their phone heard silence and then a click, and those people now think worse of you.
If your list is small and valuable, turn it off and dial fewer numbers properly. If it is large and cold, use it and accept the cost.
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