Eli5- how does phone calls work?

345 views
0 Comments

I’m so confused, like I press a button and I can talk to someone in Australia without or almost none delay? How is it so fast and how can the person even hear what I’m saying!?

In: 0

2 Answers

Anonymous 0 Comments

Think of internet and voice connectivity as different clouds ☁️ and pipes leading to these clouds as in and out connections.

Your Handset -> nearby cell tower connection in your area happens via microwaves when you call your friend in AU from US etc

Nearby Cell-tower -> your Telco’s Datacenter connection happens when cell tower receives request and sends it via underground cable to your Telco’s data-center

Your Telco Data center -> points of interconnect to receiving telco, this is where your Telco data center will forward the request to other telco (your friends phone provider)

Receiving telco -> cell tower -> friend’s mobile phones : this is the same process repeated. Cell towers know which handsets are connected to it, and thus the data center of receiving telco forward the request to the right cell tower which is in the area of your friends house

All the communication happens at the speed of light, so there is hardly any delay in setting up the connection and communication lag. There are more nuances to it terms of circuit switched networks vs packet switched networks etc but we can leave out those details for this eli5

Anonymous 0 Comments

Because signals can move really fast. Literally the speed of light. And modern technology has gotten really good at one system handing off data to another without delay. In ye olden day, the delay and lag from talking to people around the world was mostly network interconnects taking time from taking a message on one line and pushing it down the other line. The first underwater phone cables didn’t have any lag either when they tested it because it was point to point. These days all the interconnects are handled by really fast computers.

Taking voice data, encoding it, and pushing that data across the internet is it’s whole separate thing, but in short, what you hear is a recording. Even if it’s ever to temporary.