Routers vs Modems: What You Need to Connect to the Internet

To get online To reach your home, you need a modem and a router. They are not interchangeable, and serve two completely different functions. If you think of your home as an island, the modem is the port where large freighters from the World Wide Web come from, and the router is the depot that sends delivery trucks to devices scattered around your island.

But here confusion can occur: sometimes they are combined into one device. So, if you’re setting up a new network or planning to upgrade your home Internet connection, knowing the basics of routers, modems, and gateways is crucial.

If you’re upgrading your home internet, you might also be interested How to buy a router, Network vs router, The best networking systemsand Best wifi routers.

What is a modem?

A modem (or Modulator-Demodulator) acts as a translator between your home and your Internet Service Provider (ISP). It translates (or modulates) outgoing traffic, whether searches or other online actions, sends it over the Internet and demodulates incoming traffic, so the router can route it to your devices.

In the early days of the Internet, I would connect a modem provided by my Internet Service Provider (ISP) to my phone line and connect it directly to the computer through which I wanted to connect to the Internet. Ethernet cable. But that was before the days of Wi-Fi, when you could only get online with one connected device (and it was very slow, too). You can still do this with your modern modem if you’re content with having one device connected to the Internet, but most people will be looking to fill their homes with a wireless connection to connect multiple devices.

Nowadays, your modem is likely to be a box mounted on the wall where your Internet connection reaches home — or at least sitting next to it. A standalone modem is usually smaller than a router, and is often labeled, but you can also identify it by the incoming cable. If it’s using a phone line, it will have a smaller connector (maybe RJ11 or RJ22), cable modems have a round coaxial connection, and fiber modems, also known as optical network terminals (ONT), have a thin cable running inside. All devices will have at least one larger Ethernet port (RJ45) to connect to the router.

You plug your router into an Ethernet port, or you have a cable that you connect to a shared device, perhaps a gateway, that contains your modem and It works as a router. While your ISP’s modem is likely adequate for your needs, your ISP’s router is probably not so good, and you can certainly improve it by purchasing your own router.

What is a router?

Photo: Simon Hill

Your router broadcasts incoming traffic from your modem to your devices and routes outgoing traffic from your devices to your modem. It directs traffic flow, creating a local area network (LAN) in your home that devices can connect to via Ethernet or Wi-Fi. Whether you’re browsing the web on your phone, streaming a movie on your TV, or gaming on your computer, you depend on your router, which decides how to segment and divide your Internet connection between your devices.