How does voice over wire or over internet work? How can we hear and understand another person in real time over such a distance via a digital transmission?

Question

Honest question I cannot wrap my mind around. How the hell does this work?

In: Physics

Answer 1

Sound is basically oscillating air. A microphone turns oscillating air into an oscillating electric field (same basic thing as the power in your home). This makes electrons move back and forth in a wire. The electrons don’t move very quickly, but the electric field travels down the wire at around the speed of light, reaching the other end in a fraction of a second. There, a speaker does the opposite job of the microphone, turning the field back to oscillating air, hence sound.

That’s the most basic telephone. Air shakes on one end, then electrons shake in a wire, then air shakes on the other end. Real phone systems involve switching (so you can dial a number) and multiplexing (so that more than one signal can share the same wire).

In digital communications, the electric field is converted into numbers describing it ([ADC](https://en.wikipedia.org/wiki/Analog-to-digital_converter)), then the data is transmitted, and it’s later turned back to a field ([DAC](https://en.wikipedia.org/wiki/Digital-to-analog_converter?wprov=sfla1)).

I don’t think you’re asking how data is transmitted over the Internet, and even if you are, that’s a bit much for an answer in this subreddit.