Oh, sweet Jesus, I’m old.
So, some time back, there was this article about how kids could hear these ultrasonic tones that older adults couldn’t. Shopkeepers in the UK were using that to their advantage to drive away teen-age loiterers with ultrasonics. Well, those sneaky kids have turned the tables and are using ultrasonic ring tones in school. They can hear them, but the teachers can’t. Sneaky.
Oh, and if you think you aren’t old? Go to Ultrasonic Ringtones and see how many you can hear. Thanks to my tinnitus from working in server rooms, my ears are all but shot in the high frequency ranges. Also, I’m old, old, old.