Ah you are correct: https://techcrunch.com/2014/06/26/how-can-chromecast-connect-to-your-friends-phones-without-using-wifi-ultrasonic-sounds/ https://techcrunc

Ah you are correct: https://techcrunch.com/2014/06/26/how-can-chromecast-connect-to-your-friends-phones-without-using-wifi-ultrasonic-sounds/ https://techcrunch.com/2014/06/26/how-can-chromecast-connect... I couldn't remember if it actually shipped in anything, but looks like it did!