I Don’t Get I.T. : Modem vs Router

During my BSIT studies, I realized I was force-feeding myself loads of information to get through the courses and keep my 3.8 GPA.  As a result, my understanding of basic I.T. concepts went out of the window.  I could regurgitate plenty of information, but I couldn’t tell you the root of HOW or WHY.  So, I decided to blog about I.T. Basics.  My aim is to offer elementary-level backbone information a fourth-grader can understand, so anyone can build their tech knowledge.

Any questions, comments, concerns — feel free to comment.  I also take kindly to constructive criticism and if you have an I.T. question, ask away and perhaps you’ll see a future post about it!

Make sure you read my simple explanation of the Internet, first!

Accessing the Internet to view the World Wide Web on your Browser requires two things: a modem for an Internet connection and a router if you want that connection to apply to multiple devices.  What are these things?  What do they do?  How are they different?  Do I REALLY need both?

WOC Phone/Laptop

In the last blog, we talked about what the Internet is, the difference between the Internet and the World Wide Web, how an Internet Service Provider gives us access to the Internet, and how a browser is the software on our device that allows us to view information IN the World Wide Web ON the Internet.  We did not go into much detail about how the Internet Service Provider gives our PC access to the Internet, we just laid out the fact that it does. 

Keep in mind all of this is far more complicated than will be simply explained, here, but we are trying to keep it elementary-level.  So, let’s hop in so you can get I.T.!

What is a modem?

Example Cable Modem

In super simple terms, a modem is a device that grabs the Internet Service Provider’s connection to the Internet and extends it into your house!  It is responsible for allowing your computer and the Internet to understand each other.

Your computer likes digital signals.  The Internet is analog.  The Internet’s analog signal goes to the modem, the modem demodulates the analog signals into digital so the computer can understand.  The modem also modulates the digital signals from the computer back to analog.  That is where the word MODEM comes from – MODulator, DEModulator!  The modem is pretty much a translator between your computer/router and the Internet.

Analog vs Digital Signals

The Internet is connected to your ISP (Internet Service Provider).  Your ISP connects to your home using cable, fiber, or DSL Internet service.  Fiber is relatively new and quite different as it does not require a modem, so we will save that for another post.

You do not need a router if you’re only intending on having a single device wired to the modem for the Internet.  You will use the Ethernet port to connect the Ethernet wire from the modem to the single device.  The Ethernet port looks like a phone jack, but wider.  If you want multiple devices to be able to access the Internet you just brought into your house, you need a router!

Curious to know how you can tell if you have cable or DSL?  Check your connection.  Is your modem connected to the wall by a coaxial (AKA: coax) cable that twists onto a metal nub sticking out?  That is cable Internet.  Are you hooking your modem into an RJ-11 jack in the wall?  This is also called a phone jack – if this is your connection, you’ve got DSL.

[Fiber modems are a bit different as they don’t do analog-to-digital conversions the way the others do.  Fiber modems convert light signals into digital signals and the installation is drastically different along with the fact that a fiber connection requires an optical interface… again, we will save that for another post.]

Can I connect to the Internet with just a modem?

You can!  But a typical modem is really only meant to give a single computer (or a very small number of comptuers) an Internet connection and it has to be wired (Ethernet).  Some of you may be thinking, “Wait… routers move information across the Internet, so if I don’t have one in my house, how will the information move?”  There are routers all across the Internet – different kinds, too, and this can bring hubs and switches into our conversation!  But to KEEP IT SIMPLE, just because you don’t have one IN your home doesn’t mean others aren’t working far away, behind the scenes, directing traffic!

What is a router & what does it do?

In super-simple terms, your router is the box that allows multiple devices to connect to the Internet.  Your router will take the digital signal from the modem, translate it into analog radio signals, and broadcast it over to the devices.  The device’s wireless adapter will take the radio signal and translate it back to digital.

Typically, your router will have 1+ external/internal antenna(s) allowing for wireless connections and an Ethernet port to allow the connection to the modem.  Some routers have multiple Ethernet ports AND wireless antennas to allow multiple wired and wireless connections.

Why can’t I connect to the Internet with just a router?

Strictly speaking, since we are trying to keep this simple, your router cannot connect to the Internet without a modem – the modem is what connects to the ISP which gives you the Internet connection (Okay, you CAN… but… that process is outside the grade-level of this blog post).  The modem also converts the signal from analog to digital.  The router CAN, however, allow you to tap into a LAN (Local Area Network).

If you want an Internet connection, you need a modem.  And if you want that modem to give the Internet connection to more than one device, you need the router.


It is now very common for Internet Service Providers to give you a modem with a very low-grade wifi router built in.  For casual Internet users, this is typically good enough.  Most folks can run multiple devices at once with little-to-no issues.  However, it is recommended that you purchase your own equipment.  Why?  For starters, you’ll have to pay a rental fee for the device your ISP is loaning you.  That adds up over time and you’ll end up paying a hefty price for a device you could buy yourself.  Over a few months, you will have been “paid back” by not paying the rental fee.

Keep in mind it is highly unlikely you will one day decide you don’t want an Internet connection, anymore.  You’ll always use it, so if you spend your hard-earned cash on decent equipment, you’ll save quite a bit over the long-run!

Recap:  Modem vs Router

Long story short IN SUPER SIMPLE TERMS, a modem brings the Internet into your house and a router allows a multi-device connection.  Also, routers exist across the Internet to direct traffic!

For more visual learners, here’s a great video!

Media references & techies to follow on Instagram:

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