Eli5: how can a single data cable supply so many homes with different data at once, like for internet connections? Isn’t everything basically just 0s and 1s? If that’s the case how is it being organized and sent to the right place?

Question

Thanks for the answers! My biggest takeaway is about how bits work using different frequencies, and how fiber optics can use different colors to help organize data

In: Technology

Answer 1

It’s like radio. You can tune to one radio station and get a totally different channel with totally different programming from another radio station. Well, someone eventually figured out that you can also send radio over a cable rather than over the air and that lead to the creation of cable TV. Well, someone also figured out that just like your cable company can talk to you, you can also talk to your cable company for things like internet. It’s just a more advanced version of a walkie-talkie so they built a box called a cable modem that does two-way communication between you and your cable company.

Every single person on a cable gets their own channel, just like every radio station gets their own channel on the air. The frequency of the information sent over the cable is different for every person so that no two people are talking at once.

The difference between something over the air and over a cable? Over the air, there are different things at different frequencies and it’s shared over a massive area. A radio station might live at 99.5MHz and another might live at 97.9MHz but the radio signal for a military airplane lives at 200MHz so you can’t also send someone’s internet on the same channel. But on a cable, you don’t have to worry about any of that because the only people talking on the cable are those who are connected to the cable. The channels on a cable aren’t shared with the radio going out over the air. Someone’s internet can be at 100MHz and someone’s TV signal can be at 200MHz without worry about anything else so you can fit a lot more conversations and channels into one cable.

Fiber is the same way. The color red is not the color green, so you can send two signals with different colors down the exact same cable and not have them bump into each other. At the other end of the fiber, there’s some complicated tech that can tell the difference between red and green and get two totally different signals out of it!