What’s the difference between a modem and a router?

With millions of us continuing to work, learn and socialise from home, the importance of our home internet connections has never been greater. All of it is dependent on the hardware powering our home networks, which is often made up of a modem, router, or gateway device that combines the two.

For connecting to the internet, modems and routers are both essential devices. Due to the similarities between the two devices – blinking lights on the front and ethernet ports on the back – many people mistake them for one another. 

Modems and routers, however, serve very different functions. What each device does, how they differ from one another, and whether you actually need a modem and a router are all explained below.

The difference between a modem and a router

A modem connects you to the internet, whereas a router provides WiFi, or wireless access, throughout your home. This is the most basic difference between the two.

Essentially a modem provides internet access to your home, while a router provides the connection to the devices within your home and allows your devices to communicate with each other wirelessly. A modem has a public IP address, while a router assigns local IP addresses to each connected device. And finally, while a modem uses a WAN network, a router creates one. 

What does the modem do?

A modem translates analog signals from your internet service provider (ISP) into digital signals that can be understood by your devices and vice versa. This forms what is referred to as a WAN (wide area network) and your devices can send and receive data over the internet as a result. In order to be recognised on the internet, the modem has a public IP address that is assigned automatically.

The majority of modems have three ports: one for connecting to the internet, one for connecting to a router and one for connecting to a power source. While more modern modems use cable or fibre optic connections, older ones connect to the internet via telephone lines. 

In order to connect to a router or computer, modems also have at least one ethernet port. A reliable wired internet connection is provided by a modem. However, you will require both a modem and a router if you want to connect multiple devices or use WiFi.

What does the router do?

People relied solely on modems to access the internet in its early years. For a dial-up connection with your internet service provider, you would plug your modem into your home phone line. You would then connect the modem to your computer to connect it to the internet. 

Such wired connections were great for a reliable link, but they are completely impractical should you wish to connect from any room in your home or use wireless devices. For that, you’ll need a way for those devices to wirelessly connect to your modem. This is where a router comes in. 

A router forms a local area network (LAN) by sending data back and forth between the devices in the network. It then connects the LAN to the modem so that all of the devices in the network can share the same internet connection. 

With the use of ethernet cables or, in the case of a wireless router, a WiFi radio signal, it connects to multiple devices. The router directs the data flow and assigns a local IP address to each device on your network. This allows you to exchange files, print wirelessly and perform a number of digital tasks by enabling communication between your devices.

How does a gateway work?

To connect more than one computer to the internet in the past, you required both a modem and a router but, thanks to advancements in technology, we now have what is referred to as a gateway. 

This is a useful device that combines the functions of both a modem and a router. They can be helpful if you want to streamline your setup by reducing the number of devices you need to configure and manage.

However, the fact that modems can be used for a number of years while a router’s technical requirements are always evolving, is one reason to avoid buying a modem and router combo. Instead of just occasionally upgrading the router alone, you would regularly need to do so for a gateway.


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Written by Taryn Hill

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