How does data get transmitted instantly thousands of miles

[IveAlwaysWondered]

There have been a number of inventions, which I don’t know they work e.g. car, aeroplane, microwave but I can have a high level understanding of how they work.
There is one development which I really don’t understand how it works and that is video calling via mobile phones. I can face time someone in Australia and my image and voice is somehow transmitted via the air to my router, then along fibre optic cables across thousands of miles, and then via the air to recipients mobile within milliseconds. How can this be as I find it mind boggling ??

It’s witchcraft. That’s the only explanation I can think of 😂

Quantum physics

Fibre optic cables transmit information as pulses of light (rather than pulses of electricity, like old copper cables). Which is really, really fast.... that's pretty much it, haha.

gnomes. Elemental spirits like gnomes are invoked to explain things such as the working of a fax machine, to deflect children from ‘'dangerous'' analytical thinking.

But how does all the information get converted into pulses of light so quickly ? And how ? How did someone work out how to do this ?

God I am always asked DH this sort of thing. Even more simple things like I’m learning to code and I just don’t understand how what I write actually makes the physical wiring of a computer do stuff digitally or whatever. Or how even pressing a key on a keyboard makes it appear on the screen instantly. Or how someone in Australia can read this the minute I submit it.

But the fibre optic video call thing has fully boggled me even further now. Off to annoy DH 😄

There is actually a perceptible lag in transmission of the image, as anyone who's been in the same room as people on the same work video call will know.

The speed of light is 300,000 kilometres (186,000 miles) per second. A lot of data travels as light through fibre-optic cables. Light can go around the world over 7 times in one second. Pretty amazing.

It does seem miraculous tbh, we just take it for granted now. I have watched people live streaming diving and all sorts. When you get down to the nitty gritty of it I don't actually understand how mirrors work

How does light carry information?

Face into camera. Image from camera into WiFi (in our house at least), into router, down broadband cable in road, to DNS which is like a phone book for websites. Then it will essentially take you to the zoom server (we’re using zoom in this example). Then your pal in Peru, say, will be on zoom, and have a matching meeting code to you. Therefore your image will end up at them. They’re basically downloading your video stream.

But still don’t understand how it all actually gets there thoufh. Like your actual voice??!!

The internet uses packet switching. It's like sending a letter. You send some data to your wifi router with the address of the server in Australia.

Your router doesn't know how to get that data to Australia, but it knows it's not an address for your local network (e.g. your wifi printer) and so it sends it to your internet provider (ISP).

Your ISP also doesn't know how to get it to Australia, but it knows that's not an address on it's network, so it sends it to one of the global backbone networks.

That network gets it to Australia. Then the the Australian routers look at the address, and work out which Australian network it is for, and send it on etc until it arrives at the final server.

Which then replies with your address, and the whole process runs in reverse.

There is latency caused by the speed of light and time it takes for each router to switch the packet. I think to Australia it's about 200ms each way.

Ask your eyes 😉 Seriously, though... Through it being pulsed in various ways. Just as air is pulsed - which allows us to hear sound.

Still none the wiser really. Your actual voice travels through the air. I don’t get it!

There are two different things going on.

One is digitising an image - ie taking visual information, a picture, and turning it into numbers. Simplest way to think of that is first to understand binary - a number expressed just as zeros and ones. Then it's easy to think of a picture being reduced to a series of dots, and those dots being represented as zeros and ones. Something like that happens when you take a photo on your phone.

The second thing is sending the number representing the picture down a fibre-optic cable to Australia. The fibre-optic cable carries pulses of light. It can carry a binary sequence of zeros and ones quite easily, a bit like morse code. At the other end it's assembled back into the image.

All that happens very very very quickly, and a lot of images sent become a moving image.

All massively simplified, I'm not a scientist, but that's how I understand it!

But how does your literal face and voice arrive in one piece?? It’s just mad! That’s a v good explanation though for sure. The postal service doesn’t boggle me for some reason.

Literally I don’t get this either…two of my children are brilliant at maths and physics (a’s at Alevel and physics degree)

I can’t understand…and I mean it…how electricity works from its creation down to it powering a machine

i understand energy and conversion but how does it get down a line and power stuff???

im not really asking as I don’t care but I look at pylons and I’m baffled

But how does all the information get converted into pulses of light so quickly?

Light travels at 300,000,000 m/s so, at the distances you are talking about communication down fibre optic cables and using radiowaves is essentially instant.

When a current is induced in an electrical wire, all the elctrons in the wire move at once. The electrical circuits are slower than the light and radiowaves but they are still taking only tiny fractions of a second over the short distances the electric wires cover.

It doesn't arrive in one piece! It arrives in many pieces (packets) and gets reassembled. The underlying systems know the order of the packets, also if any go missing (dropped) they get resent.

It's all layers. No layer knows all the details, but each layer knows what it needs to do next.

Your laptop has a camera that converts light into digital data, and a microphone for sound.
Your laptop reads the data from the camera/mic and splits the data into
many individual packets.
It then sends these packets as described above.
etc.

Got my son a subscription to “How it works” a couple of years ago - I have learned so much from a few sneaky reads while I’m supposed to be dusting. I get a little excited when they arrive now. ( stop it !.., I don’t want your pity)

But how does your literal face and voice arrive in one piece?

It doesn't really. All the information is sent at once and reassembled almost instantly by the software displaying the image.

These things do take time but it's 100ths or 1000ths of seconds. Not always- sometimes some of the information lags, which is why video chat cuts out. Not enough info gets through for the software to creat the image and sound.

I am so glad someone has asked this!! Feeling relaxed just at the thought of almost understanding this!

I'm so glad you said this. I keep thinking "but how the fuck do they make^ glass^??!!!" so I've got no chance of understanding FaceTime

Not just through air. As a kid didn't you ever talk to a friend using tin cans and string? I can't be the only here who tried that, surely?

We did wallow talkies. But how is it not through air? My phone is unplugged and I can FaceTime my husband whose phone is also wireless. It’s wild!