What’s the Difference Between a Cable Modem and Router?


Many High Speed Internet Service Providers (ISPs) boast about the numerous benefits of their service compared to dial-up. But rarely will they mention any of the potential consequences or dangers that come along with cable modems. This article will explain to you how a device called a ‘router’ (rhymes with ‘shouter’) can help keep your computer and its data safe from the Internet. Let’s discuss the differences between a cable modem and router.

Cable modems are wonderful devices. Once you’ve owned and installed a cable modem, you probably wondered how you ever lived without one. Your cable modem connects your computer to the digital world outside your home/office to the Internet. Your cable modem is always on and is ready whenever you are.  But without proper protection, you can easily become infected with viruses, worms and spyware that can easily access and manipulate your computer! In fact, your computer could be invaded or infected without you ever realizing it. Knowing the difference between a modem and router is important.

What does a modem and router do?

A router serves three purposes:

A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information.

A common misconception is that if you only have one computer, you don’t need a router. While you may not have a need for sharing your Internet connection, data or printers, a router provides security.

All routers act as hardware firewalls. Some routers have more intelligent firewalls than others, but any router is better than none. Windows XP/Vista has a built-in firewall as do many Internet security software packages. However, all software is prone to being manipulated, disabled or otherwise damaged. Many viruses are specifically designed to do just that. Once your firewall is down, your computer will become extremely vulnerable to all sorts of Internet baddies.

Spam email messages, identity theft and the further spreading of Internet worms and viruses are jobs most commonly done by infected computers whose owners don’t have a clue anything is wrong. Infected computers are referred to as “zombies.”

Avoid Becoming a Zombie

A router can often times look very similar to a cable modem. Both are small plastic boxes with lots of blinking lights. They can look very complex and intimidating, but in reality they are extremely easy to install and use. So easy, in fact, you might forget you have one.

Note: Most cable modems do not come with routers, while DSL modems usually have routers already built-in.

To determine if you are currently being protected with a router, simply follow these easy steps:

  1. Click Start in the lower left corner of your computer.
  2. Click Run.
  3. Type CMD and click OK.
  4. Type IPCONFIG.
  5. Press the Enter key on your keyboard.

You should see a prompt like “C:>Documents and Settings\User>”

Pay particular attention to your IP Address. If your IP Address starts with 192.168.xx.xx or if your IP Address starts with 10.0.0.xx then you generally are being protected by a router.

If your IP Address contains numbers other than those, it is highly recommended that you purchase and install a router immediately.

Type EXIT and press the Enter key on your keyboard to close this window.

Which Router Should I Buy?

Comcast Internet Router
A router is a device that forwards data packets between computer networks, creating an overlay internetwork. A router is connected to two or more data lines from different networks.

There are many routers to choose from and they will all do a decent job of protecting you. Routers that offer Stateful Packet Inspection (advertised with “SPI” in big letters on the box) have the more intelligent firewalls mentioned earlier.

Do not buy a wireless router unless you need the wireless functionality. You might find wireless routers available for less money then wired routers and be tempted to buy one to save money. Don’t!

Adding wireless to the equation means adding the need for securing that wireless and offers bad guys another door from which to access your computer. If you have a laptop or a computer that would benefit from having wireless, then by all means, purchase a wireless router. A wireless router does everything a wired router can do with the added capability of broadcasting your Internet connection throughout your home/office like a small radio station.

How to Install a Router

Installing a router is similar to installing a telephone answering machine. With the cable modem, router and your computer’s power off, unplug the cable modem from the back of your computer and plug it into the back of router where it is labeled WAN or Internet. The router will come with an extra network cable. Plug that network cable into any of the available ports on the back of the router;, the other end of that cable plugs back into your computer.

Then turn on your cable modem, turn on your router and turn on your PC. In most cases, your installation is complete and no software installation is necessary.

These steps are typical of most routers, but they are not meant to supersede or replace the instructions included with your router. Please refer to your router’s documentation for the manufacturers recommended installation instructions.

What a Router Won’t Do

A router can do a lot to protect you, but it can’t do everything. Your router can’t stop you from getting a virus, it can’t make your Internet go faster and it can’t do anything about the amount of junk email you receive.

The bad guys will try to grab control of your computer using a virus, a Windows exploit or a simple electronic open door. With active and constantly updated anti-virus software, applying all Windows updates from Microsoft and using a router, you’re  doing your best to block out invaders.

Hopefully, this article helped you figure out the difference between a modem and router!

Photo credit: Mr. T in DC via photo pin cc


  1. I have a modem from my cable provider and I have had all kinds of problems. I was thinking of trying to connect a router to the modem to avoid all the attentional trouble that. I have had I have lost the sound on my computer, I cannot pull up the desktop images and I’m constantly being hacked. I have had virus trouble I never feel as if the cable company is telling me the truth. Can I connect a cable to the cable provider’s modem is that possible?

    • Hey William,

      Yes, I highly recommend getting yourself behind a router. The cable modem has no built-in protection against hacking or other bad things. Find yourself a router that has the features you need (all wired versus wired and wireless) and follow the directions that come with it.

      The cable company’s modem assigns an address to your Internet connection. Without a router, this is your computer’s address, making it much easier for bad guys to find you and get into your computer. The router helps to minimize this problem.

      On the back of the modem is the cable that goes to your computer from the modem. Remove this from the computer and insert it into the port on the router labelled either “WAN” or “Internet”. Run a jumper cable from one of the numbered ports on the router to your computer. This piece (http://qa.digitallanding.com/a-quick-belkin-router-setup-primer/) has a but more information on how to stay safe online and hook up a router. Even if you don’t own a Belkin unit, the basic steps will be the same.

      I also recommend going to the Microsoft site and downloading their Malicious Software Removal Tool. Run the tool once a week, downloading a new one each time, since new definitions are added to it daily. The address to download it is:

      Additionally, if you’re not running a quality antivirus solution, spring for the $50 and get either Kaspersky Internet Security or ESET Smart Security. They cost around $50 or so per year.

  2. Hi. I have a few questions.
    Is a cable modem the same as an EMTA modem?
    Is it possible to get an EMTA modem and a router combined?
    Do you know if Comcast will take it if they are combined?

    Thanks for the breakdown between Cable modems and Routers. Comcast got me so confused.

  3. Hi LeQuita,

    To answer your first question: Yes and no. An EMTA modem is an Embedded Multimedia Terminal Adapter. Fancy lingo for a modem that enables voice telephone over the Internet (Voice over Internet Protocol, or VoIP). These come from the Cable company, such as Comcast, who offers digital telephone service via their cable service, when they are combined with a modem. They can be bought separately also, if desired.

    Yes, if you order the Vonage service, they will send you one of their routers, which will be an EMTA combined with a 4-port wired router.

    Yes, all Cable service providers allow the use of an EMTA.

  4. Hello, I have a cable modem from SCTV which has no ability for configuration. I am limited to only 2 device connections at one time. Everytime I want to connect another computer I must reboot the cable modem. My question is, can I buy a different cable modem which will allow at least 6 devices at the same time and put it in place of the SCTV cable modem? Is there availability of a wireless cable modem so I do not need to use an additional device such as an access point or router to enable wireless?


  5. Hello,

    you could add that addresses from up to are also within private IPv4 address space.

  6. Hello. Pls i wonder if it is still possible to break up a tv decoder signal to browse the web. Actually i just got to know that but i need to be sure before buying all the needed items. Awaiting your reply soonest Thanks for your time.

  7. I am moving and will get Time Warner Internet connection (Cable), but not the TV package. I understand there are also DSL connections, which I think is telephone wiring.
    Question: Are modem/routers either Cable or DSL, so I need to get a Cable modem/router? Or can most handle either?

    I am looking to get an ac modem/router as that looks like the future for connection.

    Any suggestion on Make and model of modem/router for Cable connection? Thanks

  8. Does either the modem or router need to be connected to a computer? I want to get rid of my desktop computer. If I do that can my printer be hooked up to router to be used by my laptop? Thank you.

  9. pls what type of router should i buy for my strong satellite decoder inorder to open internet account and get dstv?

  10. Hi-I have the gateway device (modem/router in one) from Comcast that my new HP computer uses for wireless connection (we also use our ipads and kidles off of it), and I don’t think it’s as quick as when my computer was hardwired in. Is there a router that will give me the lightning quick connection and ability that my 4 year old computer had when it was hardwired in? I’ve heard good things about the new Apple Airport Extreme.

  11. Is there such a thing as a modem and router combo? We have comcast and assume a modem. Can I replace it with one router/modem combo? THANKS!

  12. We have a large house and use our cable company for a bundle package for phone, cable and Internet. When we built the house we insulated all the walls and use thicker drywall. We also put a special insulated roof plywood that tends to block signals. Our main computer and router etc is on one side of the house but we are unable to get a signal from our router on the other side of the house for the Apple TV and kids laptops. The cable tech told us to get another D3 router that has a CAT5 plug or get a special D3 one that has a special cable plug on the back that allows it to be plugged right into our cable box in our master bedroom that will transfer the signal right from our cable box. He said they are hard to find though. Does anyone have suggestions on what he is talking about and or where to get one. Or another alternative? Thanks.

  13. Thank you Thank you Thank you Thank you! I installed computer systems and worked on computer programs back in the beginning of the tech age. I can now compare working on a car before the 90’s to working on a car engine now. I ask someone for help! So, thank you again.

  14. Well, I’ll be damned. That was the problem!

    Okay, I am connected to a router but my IP does not start with the numbers shown in the this article. It starts with 68. What is wrong?

  15. hi i have an old house that has no internet ports on the wall so we had to get a modem, whene we got it it gave off wifi but we didnt use it since we only used the ethernent port, now i have a smartphone and a tablet but about a year ago my modem doesnt give ANY WIFI SIGNAL what should i do?

  16. I am in the process of getting internet installed in my house, just internet, as I am also getting a roku to watch t.v. I am trying to save as much money as I can so I was going to buy my own modem. Do I also need to buy a wireless router? Do you think Comcast will help when they install?

  17. woooow this website is super

    throwing more light on #Stanley’s question.
    please I want to know how possible it is for someone to get internet connection on a Pc using decoders like Strong, DSTV, etc as a cable network modem. please I need information on how to get that done.
    prepaid plan is way so expensive and its freaking me out.

    keep up the good work.
    thank you hoping to get your reply.

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