Router vs. modem: what’s the difference?
The modem connects your home to your internet provider. It’s the box with the cable coming out of the wall. The router takes that one connection and shares it with every phone, laptop and TV in the house, and it makes the Wi-Fi. Some providers put both in one box, which is why people mix them up.
What the modem does
Your internet arrives on a cable, a phone line or a fiber line. The modem turns the signal on that line into data a computer can use, and back again. The name is short for modulator-demodulator, which is exactly that job.
It’s usually rented from your provider and has their logo on it. It has one job: get your house connected.
What the router does
The router runs your home network. It gives every device its own address inside the house, sends each one the data it asked for, and broadcasts the Wi-Fi so devices can connect without cables.
If you unplug the router but leave the modem on, your house is still connected to the internet. Nothing in the house can reach it, because nothing is sharing the connection.
Which one to restart, and in what order
Unplug both.
Pull the power on the modem and the router.
Modem first.
Plug the modem back in and wait about two minutes, until its lights settle.
Then the router.
Plug the router in and wait again. Starting the router before the modem is online is the most common reason a restart doesn’t work.
How to tell which box has the problem
If every device loses the internet but still shows Wi-Fi bars, look at the modem: its internet or online light is the clue, and if it stays off after a restart, call your provider. If the internet works in one room and crawls in another, that’s the router’s Wi-Fi not reaching. Move the router higher and into the open, away from water and metal, before you buy anything.
Questions people ask
Do I need both a router and a modem?
You need both jobs done, but they can live in one box. Many providers rent a combined “gateway.” If your Wi-Fi is weak, you can often keep the provider’s modem and add a better router of your own.
Why does the internet work on my phone but not my laptop?
If other devices work, the modem and router are fine. Restart the laptop, or forget the Wi-Fi network on it and join again. The problem is on that one device.
Learn it by taking one apart
The app teaches this in Module 20, Two Computers, One Wire, where the crew gets Grandma Ruth’s laptop online, and the Fix-It Card for when the Wi-Fi works but the internet doesn’t is in Module 21.
How Computers Work is a course in five-minute lessons, with something to play with in every one and an old laptop the crew fixes along the way. Part I is free. Coming soon to iPhone, iPad and Android; the toys on the course page work right now.
Keep going
What is RAM, and how much do you need?
Your computer’s working space, why it forgets, and how much you need.
SSD vs. HDD: which is better?
Flash chips vs. a spinning plate, and why the swap makes old computers fast.
Mac vs. Windows vs. Linux: which should you get?
Three families plus ChromeOS, where they came from, and how to choose.