Asterisk is free/open source software for doing all sorts of things with phone calls. It allows me to handle incoming calls differently depending on who’s calling. One of the big reasons I started using it at home was so I could better deal with telemarketers. If a call matches a certain number, it gets answered by this script:
As you can probably tell, the above script speaks several random phrases to the caller and it waits each time for the person on the other end to stop talking so that they might think they’re talking to a real human. The idea is to keep the telemarketer on the phone for as long as possible. The second line saves a recording of each call. So far I’ve got one guy who stayed on for three iterations before realizing it was a computer. Of course I only put numbers on this “blacklist” that call over and over without leaving a message and are reported to be telemarketers, debt collectors, etc.
I don’t have any recordings to share right now but I found a well known example that’s basically the same thing, known as the Telecrapper 2000 (TC2K). The original is a hacked together device using an analog telephone and circuit boards whereas mine is done completely in software. There’s many examples on YouTube. Here’s a couple with good audio quality: