> The biggest step was eliminating the analog-to-digital converter that turns your voice into data. Instead, they took advantage of tiny vibrations that happen in a microphone when a person is talking into it, or a speaker when someone is listening. An antenna converts that motion into radio signals in a way that uses almost no power.

Does it mean the voice is transmitted in plaintext using analog modulation of (reflected) carrier wave? Privacy concerns aside, how can it handle calls from multiple stations over same frequency range?