How do automated calls for appointments or other things know whether a person or an answerphone picks up?


Answerphone pickups are recorded as regular (person) pickups at the exchange. How can automated calls know when to start playing their message when an answerphone picks up?

Here’s a scenario:

1. An automated call comes from your doctor/orthodontist/dentist/etc. to remind you of an appointment.
2. Your answerphone picks up and plays its outgoing greeting.
3. When the greeting ends, the script plays its message and then hangs up.

As some greetings have silence at the beginning (for a fax machine to know if it’s fax or voice) how can automated calls know whether the answerphone starts recording?

In: 5

While it will vary, there are a few tricks you can figure out from listening to the audio of the call. With a digital phone line you normally receive a notification from the service if the remote phone is ringing and when it actually answers – you don’t have to listen for that sound of ringing. If the notification of a pick-up is instantaneous with no ringing period, you can guess that you went straight to voicemail.

Alternatively, listen to the sound of the person talking. A normal person says “Hello?” or other brief greeting and you might hear line noise in the background. Voicemail babbles on and/or the background is usually cleaner when the voicemail machine is the default automatic greeting. From this you can make a pretty good guess as to whether you’re talking to a real person or sent to voicemail.