Routers vs Modems

Routers & Modems 101

When you’re building a network, there are a few essential components that show up in every design, especially if this network accesses the internet.

Somewhere along the line, you have to attach a modem. It’s essential for internet connectivity. Assuming you use more than one device with this network, you probably also need a router. Each of these devices is essential, and they are often combined together into a single networking device.

But, what are they really doing? What are the key differences between modems and routers?

What Do Modems Do?

The word “modem” is actually a shortening for modulator-demodulator. This longer name perfectly describes what a modem is doing. It modulates or demodulates carrier wave signals. Many people will tell you that a modem provides internet connections for networks. While that is effectively true, the real purpose of a modem is simpler and more universal than that.

What does it mean to modulate or demodulate a carrier wave signal?

In essence, analog signaling works via wave functions. A wave can vibrate in a specific way to carry information — thus the name “carrier wave.” When that wave is demodulated, it is changed from the carrier wave signal into something else. In the case of computer networking, your modem demodulates the wave signal into a digital signal that a computer can understand.

Modulation is the reverse. The modem is given a signal, and it then translates that signal into a carrier wave that can move across analog infrastructure.

When modems were adapted into computer networking during the early days of the internet, they primarily modulated signals to travel across phone lines. As infrastructure updates were introduced to the internet, coaxial lines, radio waves, fiber optic lines, and many other analog systems were introduced.

Ultimately, modems are still the translators that provide communication between your computerized devices and these analog networks that carry information across great distances.

How Do Routers Work?

A router is an entirely different piece of networking equipment. This is a device that tells incoming or outgoing information where to go. As the name implies, it routes traffic.

In practice, this is the device that allows you to connect multiple other devices to a single internet node.

Let’s use a common home network as an example. In your home, you might have multiple phones, smart TVs, and even computers that all access the internet. Despite that, you only pay for one internet access point, or one internet line.

The router manages all of the data traffic in your home so that these devices can effectively share that single access point to the internet.

It’s worth noting that routers can do this with both wired and wireless connections, and most modern routers do both at the same time. You can plug multiple devices directly into the router, and you can connect many more wirelessly. A single router can handle both tasks with ease.

What Are the Primary Differences Between Routers and Modems?

When you think about the separate functions of modems and routers, it’s easy to see how they might work together. Sticking with the home network example, the router manages all of the information inside of the house. It then passes that managed information to the modem.

The modem then sends the information along the greater internet. For incoming data, the modem receives every packet of information that will eventually make it to any of your devices. Once the modem receives the packets, it then demodulates them into digital signals and hands them off to the router. From there, the router can direct the traffic to the correct device.

Because both devices are critical for modern networks, they are often combined into a single all-in-one unit. Such an all-in-one unit actually has a separate modem and router device under the hood, but you only have to plug in a single device.

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