Computers & Mobile
Stop robot callers with a tone


Aparently there’s a U.S. Special Information Tone signal for a dead phone line, and robot callers (telemarketers, debt collectors, etc.) listen for it, then remove the “dead lines” from their lists. Record it at the beginning of your answering machine messages to make (some) robots stop calling you! [via] Link.

(Photo by Flickr user scriptingnews)

20 thoughts on “Stop robot callers with a tone

  1. Um, or just submit your phone number to If you get a telemarketing call you get after that you can get them heavily fined, so they don’t.

    I signed up years ago and haven’t gotten a single telemarketing call since.

  2. I seem to remember buying a device, I believe it was called a “phone zapper”. I plugged it in and havent gotten a telemarketer call since.

  3. The “Phone Zapper” and similar devices simply respond to calls with the dead-line tone. The unintended consequence of putting this on your answering machine is that people you actually want to talk to may think your line’s out of order and hang up.

  4. @MadScott: Your friends and family will only hang up if they don’t wait long enough to hear you say “Hello” or your outgoing answering machine message.

  5. Some high schools have an automated phone system that calls parents when their student is absent. Playing hooky just got easier.

Comments are closed.


Becky Stern is a Content Creator at Autodesk/Instructables, and part time faculty at New York’s School of Visual Arts Products of Design grad program. Making and sharing are her two biggest passions, and she's created hundreds of free online DIY tutorials and videos, mostly about technology and its intersection with crafts. Find her @bekathwia on YouTube/Twitter/Instagram.

View more articles by Becky Stern