Routers vs. Modems: What You Need to Get Online

To access the Internet to enter your home, you need both a modem and a router. They are not interchangeable, and serve two very different purposes. If you think of your home as an island, the modem is the port where the big cargo ships come from the world wide web, and the router is the warehouse that sends the traffic to the devices around your island.

But this is where the confusion can begin: Sometimes they are combined into one device. So, if you’re setting up a new network or planning to upgrade your home network, knowing the basics of routers, modems, and gateways is essential.

If you are planning to upgrade your home internet, you may also be interested How to Buy a Router, Mesh versus router, The best Mesh Systemsand The best Wi-Fi routers.

What is a Modem?

A modem (or Modulator-Demodulator) acts as a translator between your home and the Internet Service Provider (ISP). It interprets (or transforms) your traffic, whether it’s browsing or other internet activity, and sends it over the Internet and removes the incoming traffic, so that the router can use it for your devices.

In the early days of the Internet, I used to plug an ISP-provided modem into my phone line and connect it to the computer I wanted to use to access the Internet. Ethernet cable. But this was before the days of Wi-Fi, when you could only access the Internet with one connected device (it was painfully slow, too). You can still do this with your current modem if you’re content with just one device on the Internet, but many people look to fill their homes with wireless cables to connect multiple devices.

These days, your modem is probably a box mounted on the wall where your internet access enters your home – or located right next to it. A stand-alone modem is usually smaller than a router, and is often labeled, but you can identify them by the incoming cable. If it uses telephone cable, it will have a small connector (either RJ11 or RJ22), cable modems have a round coaxial connection, and optical fiber modems, also known as Optical Network Terminals (ONT), have very little cable running.

You either connect your router to an Ethernet port, or you have a cable that you connect to a connecting device, perhaps a gateway, that has a modem. and it works like a router. Even if your ISP’s modem is good for your needs, your ISP’s router may not be the best, and you can control that by purchasing your own router.

What is a Router?

Photo: Simon Hill

Your router broadcasts incoming traffic from your modem to your devices and directs traffic from your devices to your modem. It manages 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, watching a movie on TV, or playing games on your PC, you rely on your router, and it decides how to share your internet and share it between your devices.