I found out that many devices as PCs, TVs, cellphones and more can use a technology called ultrasonic cross-device tracking. This means that there are ultrahigh sound frequencies which propagate from device's speakers and are received by nearby microphone embedded in other devices. This allows to transfer data.

Is there a way to capture these signals? Is there some app maybe that listens to Ultrasonic frequencies and let's me know what type of info is been transfered?

  • You have speaker and microphone interchanged in your question above. I think it is possible to find apps that can cut out certain frequency ranges. So, if you were to take your phone near the TV and have the app listen to the TV and make a recording while it cuts out say, everything below 15kHz, you'll have a file. Then, you'd have to shift that file many octaves down and you'll hear something. If all else fails, call one of these guys. youtube.com/watch?v=89vNqmZYgZE !! Aug 12, 2021 at 18:58
  • Yeah you are right I mixed them Aug 12, 2021 at 19:02
  • you answered your first question before you asked it
    – jsotola
    Aug 14, 2021 at 19:41
  • @jsotola what do you mean? Aug 14, 2021 at 20:01
  • in the second paragraph, you asked Is there a way to capture these signals? ... in the first paragraph, you said ... received by nearby microphone embedded in other devices .... so, the answer is yes
    – jsotola
    Aug 14, 2021 at 21:17


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