Router, modem or switch — what is it?

When you got internet installed, someone left you with a black box. That person may have called it a router, modem or switch. What is it really? Do all these terms mean the same? While the IT pros lean back and chuckle, let’s discuss the basic question… what is that black box and what does it do?

Chances are, the little black box is a router, a modem, and a switch, but maybe not. These are actually three different roles for the little black box, and it’s probably doing all of them.

A router


No, not that kind of router.

In order to get on the internet, you need three things. First of all, you need a device that tells all the other devices in your home or business where the internet is. Your home router is like the on-ramp to the internet. When cars get on the on-ramp, they line up and all start going a consistent speed, eventually merging with other traffic on the freeway. On the other hand, all the traffic that wants to go anywhere in your hometown takes the same off-ramp, and it all goes different ways once it gets off the freeway.

That’s kind of what a router does. A router is a single point where all the internet traffic in your home or office passes through. It controls access to the internet and limits outside access to your home devices. It’s like the on-ramp.

The modem


Yikes that’s an old modem.

First things first: what we call a modem really isn’t a modem. A modem is like the thing in the picture. It changes data into sound so it can go over a phone line. Thankfully it’s been a lot of years since we needed to do that. But, words have a funny way of sticking around. Just like we roll down the windows (even though we don’t use a handle to roll anymore), the word stuck around for a new generation. It even kind of means the same thing.

Today’s modem changes information so it can travel along a different kind of wire. At home that could be fiber optic or coaxial cable, or for areas still served by DSL, copper phone lines. Technically the right term for that is a multiplexer but why get technical… people call it a modem so it’s a modem.

The switch


Seriously, who’s getting the photos here?

If a router is like the freeway on-ramp, the switch is more like the stoplight in town. A switch lets you connect all your devices (wired or wireless) and makes sure that all the information gets from place to place without bumping into anything. It holds up some traffic to let other traffic through, and that makes everything flow smoother.

If you connect more than one computer to the internet, or if you have a wireless printer or even a smartphone or tablet, you need a switch to make sure everything can connect.



Your significant other would freak if your home office looked like this.

In the past, the router, modem and switch were separate huge pieces of equipment. In large commercial installations they still are. However, for home use, the router, modem and switch are usually combined in one device that does all three functions. When you connect to the internet, it acts first as a switch… getting your data from place to place in the house, then as a router… getting your information ready to go out to the internet, then as a modem… changing that information into a form that can travel on the outside wires. It does this quietly and without any fuss at all. That’s really kind of amazing when you think about it.