Home Networks & Wi-Fi · How Home Internet Works · Lesson 1 of 5

Modem, Router and Your Internet Company

Meet the boxes that bring the internet into your home.

The boxes that bring you the internet

Your home internet starts outside your house. An internet service provider, or ISP, is the company you pay for internet. It runs a line or sends a signal to your home.

That line ends at a box called a modem. The modem's only job is to talk to your ISP. It turns the signal on the line into internet your home can use.

A router is the box that shares that internet with all your devices. It makes your Wi-Fi, which is internet sent through the air by radio. It also has Ethernet ports, square sockets where you plug in network cables for wired internet.

Think of it like water. The modem is where the pipe enters the house. The router is the plumbing that carries it to every room.

Many ISPs now give you one box that does both jobs. This is called a gateway, or a modem router combo. If you only have one box and it makes Wi-Fi, it is probably a gateway.

Your devices are the last part. Phones, laptops, TVs and game consoles connect to the router, by Wi-Fi or by cable.

Knowing the parts helps you guess where trouble is. Most modems have a light marked Internet or Online. If it is off or red, the modem can't reach your ISP. Your Wi-Fi may still show full bars, yet nothing loads, because the router has no internet to share.

On the practice computer, tap each part of the home network to learn its job. Then look at the modem's lights and pick where the problem is.

Cable, fiber, DSL and 5G

ISPs bring internet to homes in a few different ways. The kind you have affects your speed and which box you need.

• Cable uses the same wire as cable TV. This coaxial cable is a thick, round wire that screws onto the box. Cable is common and fast for downloads, but often much slower for uploads.
• Fiber uses thin strands of glass that carry pulses of light. It is usually the fastest kind, and uploads are often as fast as downloads. Instead of a modem, fiber uses a box called an ONT, short for optical network terminal. It does the modem's job.
• DSL uses your home phone line. It is older and usually slower. The farther you live from the phone company's equipment, the slower it gets.
• 5G home internet uses a cell phone signal, just like your phone does. A gateway sits near a window to catch the signal. There is no line to install, but speed can change with distance from the tower and how busy it is.

Some country homes use satellite internet, from a dish on the roof. It works almost anywhere, but often has more delay.

Not sure which you have? Look at your bill, or at what plugs into the box on the wall. A round screw-on wire means cable. A phone-style plug means DSL. A thin cable from a small wall box often means fiber.

Whatever the kind, the router's job inside your home is the same. It shares the internet with your devices.