We had a TV that used ultrasonic sound to control the TV, When I was young I could fairly hear the tone from a couple of the buttons, though super faintly, but the dog would cock its head when certain buttons were used.

We had one of those TVs when I was a kid... and our dog had one of those metal link collars, and when she would shake her head the TV would change channels, and the volume would change. :). I had forgotten all about that.