It's harder to conceal a spoken command than a keypad-entered code. Spoken words are unavoidably broadcast to nearby surroundings, but you can mask your use of

It's harder to conceal a spoken command than a keypad-entered code. Spoken words are unavoidably broadcast to nearby surroundings, but you can mask your use of a keypad easily. https://en.wikipedia.org/wiki/Parabolic_microphone https://en.wikipedia.org/wiki/Parabolic_microphone