Grumpy Old Geeks Topics Ultrasonic voice commands Topic Ultrasonic voice commands 2 mentions in 1 episode The hosts describe commands sent at ultrasonic frequencies to voice-controlled devices. Mentions 226: A Badder Meinhof Sep 11, 2017 47:54 Ultrasonic frequencies can basically be used to send codes. 48:12 It’s not just Siri and Alexa.