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How to Replace a Comcast Modem with your Own (in 4 Easy Steps)

Last updated by on 61 Comments

Not too long ago, I highlighted 3 ways to get rid of your Comcast modem rental fee after Comcast killed my old Netgear gateway.

I had successfully tried the Comcast negotiation route before – but it’s easy to forget to call in to negotiate every 6 months to do so. And when you get a discount on your modem rental, it leaves you with little leverage to negotiate bigger discounts on the cost of the internet service.

Besides. I hated seeing a device with a little “XFinity” logo on it sitting next to my computer.

So I decided to replace the Arris TG862 Comcast-owned gateway, with my own.

Now, I am no longer paying the ridiculous $8 per month rental fee for a Comcast modem.

Here is How to Replace a Comcast Modem with your Own, in 4 Easy Steps:

I will specifically detail how I replaced a Comcast modem with my own, but this should be applicable to other ISP’s as well.

1. Buy a Compatible Modem & Router or a Gateway to Replace your Comcast Modem

how to replace comcast modemYou do not NEED to buy a 2-in-1 gateway device, such as the one Comcast commonly supplies. You can go with a basic cable modem and pair it with a wireless router.

There is a list of Comcast supported cable modems that are compatible with their network. Comcast recently upgraded their network to DOCSIS 3.0, but it is backwards compatible to previous generation DOCSIS model modems.

The tech I had spoke to previously had recommended the now obsolete Motorala SBG6580 gateway. After doing some research, however, I had noticed that this device had horrible reviews due to a number of problems working with Comcast’s network through firmware (or lack of) updates.

Instead, I opted to go for the Motorola DOCSIS 3.0 SB6121 cable modem (there is also a newer SB6141 model), paired with the Medialink Wireless-N router. Both were top sellers in the cable modem and router categories on Amazon and had outstanding reviews. I paid a total of $95 ($75 of which was Amazon gift cards), which means the devices will pay for themselves in just over a year.

2. Call Comcast to Activate your Modem

After you get your new gateway or modem/router combo, you’ll have to call Comcast to activate your modem. Select “technical support” when you call in. When you are connected to a tech, tell them you bought your own new modem to replace your Comcast modem.

They will start by asking you for the MAC address and Serial Number listed on your new device so that they can send a signal to your device. I’ve had my share of bad Comcast customer service experiences, but this one was surprisingly positive and simple. The tech walked me through getting my internet up and running with my new modem. Within 5 minutes, I was connected at 25 mbps download and 4 mbps upload – the same speeds I had from the Comcast Arris gateway.

The Comcast tech also removed the modem fee code in my billing profile (I didn’t have to ask for this, but you may have to). Finally, he gave me the address of a service center to return my Comcast modem.

3. Connect your Devices to your Router

Once you have your modem and router running, you should secure your wifi network and connect your devices.

You can easily set your network name and your password on your router. You’ll then need to go back to each device (laptop, cell phones, tablet, etc.) to choose the new network and enter the password.

Each router will have slightly different instructions on how to do this, but all you need to know is that it’s a fairly simple and straightforward process. Total time invested was about 15 minutes.

4. Return your Comcast Modem!

Don’t forget to return your Comcast-supplied modem or gateway. The tech told me I had 45 days to due this before Comcast listed the device as missing and charged me for it. Surprisingly, you will not be charged for the device in the meantime, you just need to make sure to return it within the 45 days.

Here is a list of Comcast service centers. They are generally open Monday – Saturday during normal business hours.

Make sure to get a receipt for your device return! I have heard of a few examples where the returnee did not do so and ran into problems. Any time you can keep a paper trail with Comcast, it’s usually a good thing, so you don’t end up with unwarranted fees later on.

Replacing your Comcast Modem Fee Discussion:

  • Have you replaced your Comcast modem with your own?
  • What gateway or modem/router combo do you personally recommend?

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About the Author
I am G.E. Miller, & this is my story. My goal is financial independence ASAP. If you share that goal, join me & 7,500+ others by getting FREE email updates. You'll also find every post by category & every post in order.

  • Michelle says:

    I actually had a great experience with a Comcast subsidiary named Cox, which is in RI. After 6 months we were allowed to keep our modem. We did pay a rental fee in that time, but the total spent on rental fees was less than buying a new modem outright. We took that modem with us when the Coast Guard transferred me to MI, and we have paid zero in rental fees and didn’t have to remember to turn old hardware back in. It was great. If you live in RI and use Cox, make sure they are giving you the modem like they did for us. It will save you easy money, and that always feeds good!

  • Yero says:

    Definitely a good investment. I have Verizon FiOS now, which offers free modem/router combo. But when I had Comcast, they charged a modem fee. I already had a wireless router, because Comcast didn’t offer one (free OR paid).

    I bought my own modem (Motorola Surfboard SB5100 Cable Modem, $29 used). It was cheap, but I know I didn’t buy the latest DOCSIS version, so it wouldn’t be useful forever. It paid for itself in about 5 months, and was then used for another year before switching to VZ. It’s now sitting in a box. I should resell to get even more money out of it.

  • Curtis says:

    If you are signing up for NEW Comcast service and want to avoid the modem rental you should be careful to avoid extra installation charges (up to $99). You can usually do a self installation (free) if you rent a modem from Comcast. I was not offered the option for a self-installation because I had my own modem, which I bought on Ebay. If you sign up your service over the phone be sure to tell them that you want to try a self installation. They will only have to send someone out to connect you if your address has been disconnected at one of their service boxes. That’s not usually the case unless comcast has never been used at your address or if it hasn’t been used for a long time.

    In the online system you will be forced to schedule an installation, which WILL incur an extra charge. I only found this out after getting a $99 surprise on my first bill. After calling and talking with them I managed to reduce this installation charge to $35. The first time I called I got put on hold and transferred in circles – typical customer service nightmare – but the second time I got a very helpful rep who was friendly and quickly resolved the problem. If you try to sign up for new service with your own modem you might have to schedule an installation but you should call to cancel it later to avoid an extra fee.

    • G.E. Miller says:

      Interesting. Thanks for sharing the tip, Curtis.

    • Michelle says:

      Really? I was able to do a self-install with my own modem and didn’t get charged for it. Just had to call and get my modem verified. They also needed to run a new wire to the house from the service box, but didn’t charge for that either. Sounds like you got a lousy customer service agent!

    • jelabarre says:

      And if you decide to upgrade to a “triple-play” plan, they’ll charge you $99 for the internet *AND* $99 for the phone. And with that the “installer” had to borrow my punch-down tool to hook the phone connection into my wiring (and within a week I had to replace the crappy connection their “installer” did with a cable I crimped myself). And consider that the $99 internet install price was to install an internet connection I already had! Got them to back down on the phone connection, but they never gave on the internet. Just waiting until/if Fios gets extended to my area (don’t hold your breath). Would go to Verizon’s DSL/Phone/DirectTV bundle, except sat. won’t work at our location.

      And that phone/internet box that Comcast provides and charges me rent on? It has a bad backup battery in it, and Comcast wants to *SELL* me a new one! What??? you mean **I** have to buy a battery for *their* equipment??? Yeah, if I were buying anything it would be a replacement box that *I* own, and tell them they can stugff their new battery and their $7.00 rental fee.

  • Tim says:

    Hi G.E. it actually can be even easier to get your own modem in that you do not need to call in. Assuming Comcast’s system isn’t having issues, you can just connect the modem and then connect a computer to the modem (I’d hold off on hooking up the router until the modem is connected, just to make troubleshooting easier but you can if you want :) ) and go through the automated activation using Comcast’s Walled Garden system which actually now has a pretty slick web GUI to guide you through the process. It’s a nice feature for people like me that hate calling Comcast hehe. I believe the URL you want to type in is

    Also, gateways are a bad idea, it’s much harder to diagnose problems :) Good choice on the SB121 though, its the one I have!

  • Teresa says:

    Hi G.E.,

    I thought I was smart by replacing the Comcast router with my own, now I have to try this and go one step further! I can’t stand how high my bill is.

    Although this article was informative, it wasn’t my first motivation to contact you. Because I couldn’t find your contact information anywhere, I figured that this would be my best bet.

    I am emailing you on behalf of Conestoga Bank, a full service bank with 16 branches and locations based in and around the Philadelphia region. I just wanted to let you know that you’ve been featured in Conestoga’s quarterly personal finance newsletter, The Good Life, in its Summer 2012 edition that was just sent out to our 5,000 readers. Please find the feature here:

    20 Something Finance was chosen by Kiplinger’s Cameron Huddleston as one of the best personal finance blogs worth reading, which is definitely an achievement to be proud of. Along with a link to your site, there is a blurb letting our customers know about your solid advice on how to save money and your impressive feat of 85% savings rate.

    We’re really impressed by your blog, and we will continue suggesting it to our customers to help improve their personal finance management!

    Please feel free to email me with any questions.


  • Alex says:

    Great write up. I actually came across a modem that was a few years old at a yard sale and picked it up for $5 (which is the per month rental fee from my ISP) It works like a charm! I get my full download speeds and it’s great. I know I was just lucky to find it but I’m thrilled I don’t have to shell out the rental fee every month!!

  • Aaron says:

    Thanks for this post! I’m moving out of the parents house and into an apartment and if not for reading this, I probably would’ve rented the modem from Comcast for $7 a month. Instead, I got the exact one you recommended and it should pay for itself in just over a year. Great advice!

  • montecisco says:

    Hi guys

    I just switched to comcast xfinity and have my fios verizon actiontec router which i didn’t have to return.

    I was thinking of hooking it up to the comcast co-ax cable and see how that works.

    Two questions –

    1. Just replacing the ARRIS with Actiontec won’t be enough right ? I will have to call or use to activate the router ?

    2. I also have phone service through Comcast and i see a phone cable running from the back of the ARRIS to the wall jack. I think this is what is providing phone service to rest of the phone jacks in my house. I don’t see any place in the actiontec router to hook up the phone cable. So question is how can i replace the ARRIS and still keep my phone service ?

    • Tim says:

      If you have VOIP service through Comcast, you have to use their supplied gateway/modem.

      Also, I’m not sure if you could even use the FIOS modem with Comcast. I know Verizaon uses Coax cables in the home but not sure if its signal compatible with traditional cable or not…

  • Sabrina says:

    I’m considering contacting Comcast for internet service only in my townhouse. I only have an iPAD, do I need a computer to set up these components?

  • Gwen says:

    Hello . . .I read your clear instructions about acquiring and installing our own modem. I can’t seem to find a modem that has internet, wireless,router, and telephony. So I have this Motorola modem that has everything except the telephone modem. So if I buy a telephone modem, how do Iconnect both to the one cable hookup. Is there a splicer of some kind. Does anyone else sell a modem that does all, so I can get rid of that $7 monthly fee? Thank you for your help.

  • Jaime says:

    Thanks for the clear instructions. I just made the swap and it was pretty painless. I only had to provide the MAC address. I also upgraded my Wifi router to a dual band “N” type. I recommend doing the modem first with old router, then the router….

  • James says:

    Okay, so that means that you NEVER have to pay for a Internet bill again?

  • Gary says:

    Do you need a better modem to run 2 iPads and 2 iPhones plus a computer. My service seems to be running slower. Not sure if you need a better router or modem. I do have up a Cisco Linksys EA2700 router 3months old.

  • Randy says:

    I have basic internet access with Comcast Xfinity. I rented the RCA DCM425C + the Netgear 150 WNR1000 wireless-N router over a year ago. I pay $14 to rent the wireless Netgear per month. My total internet bill per month fluctuates for unknown reasons, but an average of $90 per month is the cost. I use the internet to check my email, watch youtube and browse websites so I don’t use much bandwidth. Comcast calls me every few months advertising they will ‘save me money’ and lower my internet bill to just $50/mo if I subscribe to their cable tv service.

    I have had Comcast on/off over the years since 2005. I have moved several times over the years and always promptly return the equipment 2-3 days after disconnecting the service. I go and drop it off then ask for a receipt, but the Comcast personnel always tell me I don’t need a receipt. The next time I go and get Comcast again years later after moving they hook up internet then when my bill comes in the mail my first bill is $240. I call and ask what happened and they claim I never returned their equipment last time I had internet access with them and $180 is the cost of the cable modem box plus the wireless router box.

    I’m afraid to swap out the modem thinking they will either keep charging me rent for a modem that I bought and or claim I never returned theirs after I move again/disconnect service.

    I hate Comcast Xfinity, but I choose them because I’ve seen too many people who have constant connection problems with Qwest/Century Link meaning bad phones lines and long wait times on the phone. It all comes down to being extorted by the Comcastic butt-pirates, not having unreliable internet or not having internet at all.

    In short, I’m just warning everyone of the ways of Comcast if you think you’ll save some money by outsmarting them.

  • TOM says:

    It isn’t clear to me if there is a modem / router I can buy with phone port. So do I still need to pay Comcast monthly or is there a solution out there?

  • Junebug says:

    Comcast told me I have to have the Arris TG862 because I have a phone on it. They said the phone won’t work with a router and a modem.

  • dominic says:

    I wanted to add my recent experience with xfinity. I currently run a phone and an 8 way wired router off my modem with another wireless router. This supports the 7 or 8 computers we have in addition to smart phones and kindles. Xfinity had an offer to swap my modem for a newer faster one. The switch should have been seamless. Right. Just 3 simple connections, the phone jack, cable and internet connections and reboot the router. There is also an automated number to reconfigure. Well after many hours of phone calls and needless waiting I finally gave up and just put my old modem back in.

    I worked in DP programming my entire career and for the life of me all these guys are good at is developing automated and confusing answer menus. There must be a better way to upgrade a modem.

  • Janine says:

    We have d-link right now and I think it is losing its power….I am not a tech person:-) We have a comcast modeum, what would be the best to do, get our own modeum with a new router, or get a gateway through comcast…..

  • Alex says:

    Hi G.E.,

    Thanks for the helpful tips and links and advice, etc. I just recently got my first apartment and signed up for Comcast. I decided to rent the Gateway for the first month while I hunted for a good modem/router to use in its place.

    Since this post is from last summer, do you (or anyone else) have a sense for how much the technology has changed in the last year? Is the equipment you mention in the post close to being obsolete, or, if I purchase it now, will it last for a few years?

    Are you still happy with equipment a year later?

    • Tim says:

      The Motorola SB6141 or SB6121 are two of the best options. The SB6141 is a bit newer and adds additional channel bonding options for future proofing but more ISPs have yet to fully utilize the SB6121’s hardware. The price difference is small though so if you can spare the extra ~$15 you might as well get the newer model :).

  • Jeff says:

    I tried doing what the article by G.E. Miller said to do and was totally blown off by Comcast. First they won’t just turn on the new modem, not without having their own modem back in their sticky little hands. They tell you to wait 24 hours for you’re modem to activate, that’s a bunch of BS. I finally decided to put the Comcast modem back in service until I could get to a Comcast service center to return their modem. I will put up another posting after I complete that. Then I will let you know how it turn’s out.

  • RKB says:

    Thanks for the info from “How to Replace a Comcast Modem with You Own – 4 Easy Steps.
    Can you tell me if the Motorola DOCSIS 3.0 SB6121 cable modem paired with the Medialink Wireless N router would work with my wireless Comcast services: telephone, Internet and Xfinity cable?

  • Sylvia Mills says:

    Thank you so much for writing this article. I have been on the phone with Tech support with comcast for 3 days in a row now. I am paying for upload and download speeds of 15 and 20 and I am only getting .32 and .29. Of course at first they said it was my own fault and it was my equipment that was faulty. Then they said for a $55 fee for a tech guy, agree to sign up for their cable service and rent a new modem from them for $14 a month, they could have me back up and running properly again. When I abosulely refused, she then said that the modem they installed at hook up was out dated the day they installed and they are gonna send a tech guy over here to replace it with the exact same modem (that is outdated). So after shedding many tears, talking to my tech savy son and doing an internet search I found this article. I will be purchasing a new modem today and hope they don’t give me anymore trouble when I hook it up. Thanks again for all the information that this article has provided me.

  • Jeff G. says:

    hi, I’m posting this on behalf of my retired friends who are having on-going issues with comcast deleting their personal emta modem’s settings so that they lose internet and digital voice.

    regarding some of the comments above, you can use your own personal emta modem instead of comcast’s. search on the site for the list of approved and supported modems. BUT beware you may have issues going forward. see what follows:


    – they started with comcast internet only 2 years ago. they used their personal modem (provided by me) the entire time and had good reliable service.

    – 2 months ago they got an HDTV and upgraded to the triple play using the comcast technicolor gateway (GW).

    – 4 weeks ago, they asked me get them a replacement GW to avoid the monthly lease fee, $8.

    – 3 weeks ago I purchased an arris tg862 which is listed on the comcast site as a supported replacement and called comcast to get it setup. first 2 CSR failed to get the modem activated and disconnected me. both seemed relatively clueless of what needed to be done and when problems arose, how to work around it. third CSR was professional and competent and finally go the GW activated. It took 3 hours total time on a saturday.

    – they returned the comcast GW the next tuesday. 2 days later, they lost internet connectivity and phone. I came over, called 800 xfinity number and found out the modem info (CMAC, EMAC) were both deleted. CSR didn’t know why or how this happened, but 30 minutes later things were back up. for the trouble they offered $50 credit.

    – 9 days later, they lost connectivity for phone and internet. they called the CSR and again all the modem info is deleted. 30 minutes later it’s back up.

    is this acceptable? why and how doe this keep happening? the message seems to be, you’re going to have problems if you use your own equpiment. for elderly people, this is a big headache that they do not need. currently they are debating if they should stay with comcast or switch to u-verse which is also available in their area.



    • G.E. Miller says:

      I’ve never had the problems you are mentioning with the Motorola 6121 (recommended in this article) in the almost 2 years I’ve had it. Their compatibility varies by modem from what I’ve heard and they really do cater to the 6121.

  • Diablo says:

    There is a new version of the cable modem you recommend…
    ARRIS / Motorola SurfBoard SB6141 DOCSIS 3.0 Cable Modem

    would you recommend buying this one instead for $20 more?

  • The World Wide Web says:

    Awesome man…just ordered mine right now! Will get it Thursday and let you know how it goes

  • Diablo says:

    Say, I was about to replace my modem with the SURFboard Motorola when I realized the current modem also has a phone jack and the Motorola doesn’t :(
    Was so bummed, is there another version you would recommend that also includes the phone jack?

  • Diablo says:

    Just read the Ooma review, one question..does Ooma have redundancy features where if during a natural disaster like earthquakes one can still make calls?
    I asked Comcast about this when they signed me up for triple play and they told me they actually have mobile trucks that would be dispatched to keep the VOIP network running in that situation.
    The land line is really just for emergencies for us since we use our mobiles pretty much all the time.

    Is this how everything would connect?

    (comcast coxial)—[new cable modem] —-[wireless-router]—-(home network)

  • Fab says:

    I have the TG862 from Comcast. Issues I have is the connectivity is very bad / none when in my house 40 ft away from the device (this is thru a few walls).

    1. If I get the combo Motorola DOCSIS 3.0 SB6121 cable modem + Medialink Wireless-N router, will I get a stronger signal than I currently have and then get a good connection in all my house?

    2. I found have an older wireless router Cisco Linksys WRT120N. Assuming it is not good enough anymore. Am I right?

    Thanks a lot!

  • Lefty says:

    After viewing the list of Comcast-compatable modems, I bought an Arris TM722 modem for cheap on eBay to replace the one I was renting from Comcast several years ago. It works fine-I’ve never had any problems with it. It does not have wireless capability, but I have a stand-alone wireless router to support it. The modem paid for itself in just over one year. Save some bucks and purchase your own modem VS paying Comcast’s rental fees!

  • Diablo says:

    Well I just bit the bullet and bought an OOMA + wireless phone for $120 from Costco (they had a sale). Setup was super quick and easy, call quality is great (installed it Wednesday 8/8/2014.

    Is there anywhere else I can get an additional wireless phone for my second floor for cheaper than what OOMA sells it separately which is $50.

    So now I’ll REORDER the Motorola DOCSIS 3.0 SB6121 cable modem which I returned to Amazon back in April and finally return my current DOCSIS 2.0 modem to Comcast.
    Turns out I should be getting 20Mbps d/l but I’m only getting 9.8Mbs because of the modem the Comcast Rep said.

    So now I’ll be down to internet/TV from Comcast and I asked the same rep if I cancel my current package could I sign up for some of the cheaper promotional packages I see online and they said yes. I thought Comcast wouldn’t allow that if you were a current customer? All I really watch on my current package are the HD channels and nothing else.

  • Diablo says:

    OK I did it! Just went live with my new ZOOM 5341J, I bought the Motorola 6141 but read all the horrible reviews online and didn’t even open it and returned it to Amazon and went to bestbuy and got this one. Registering was a snap, took 10 mins total with a rep online. My laptop connected directly to the modem I get 57.75Mbps d/l and 4.79 u/l speeds. But through my wireless I only get 9.85Mbps so I now know the wireless router is my bottleneck. It’s an older wireless so I believe newer wireless routers can transfer at higher rates so I can get faster downloads. But just happy I replaced my old modem with this new one

  • Pieinear says:

    Hi G.E.

    I found your article concerning the Comcast Arris TG862 Gateway.
    My family put up with it for three months after agreeing to take it after negotiating a lower monthly rate.

    What a mistake. I had an angry wife. Not a day went by without having to reset this P.O.S. Comcast has great bandwidth in my area. I do not understand why they want to blacken their reputation by providing this junk 3 in 1 gateway.

    I bought the recommended modem and router from Amazon last Friday and installed them Tuesday. was on the phone with Sheila from Comcast for about 30 minutes because I could not attach the ethernet cord to my Macbook Air. She is a great service person.

    Bottom line. This set up is the fastest problem free wireless that I have ever had. Happy Wife…Happy Life! Thank you for your article!

  • Ron says:

    So can someone tell me? I am trying to replace my comcast modem Arris Mod-TM602G/CT with a SB6141 only to find only three plugins on the back the TM has four the one I need for my wireless router so now what?

    • Diablo says:

      I assume you also have voice through Comtrash? that 4th plug is your phone line which the SB6141 doesn’t have.

      Read my earlier post in this thread since I ran into the same issue and just went with OOMA for my voice.

  • BCS says:

    Comcast is sketchy. We just purchased a new Arris modem. After just disconnecting my Comcast modem and reconnecting the new modem, the tech attempted to send signal multiple times, he could not successfully send the signal to the new modem… So I had to keep the Comcast modem unless I wanted to pay to have a tech come out (I don’t think so) (HOW CONVENIENT). These cable companies need to be investigated- Just like the guy above when they deleted his modem information out of the system as to drop his connection when he bought his own modem- ridiculous companies. Dropped them for TV as well- Roku is SO much better, no commercials, a TON to watch, and CHEAP!

  • Denise Davis says:

    I have 1 tv with an HD digital dvr, 2 tvs with HD digital cable boxes and 7 tvs with the little bitty boxes that run about $3 a month, which dont even give me all the channels I am paying for, and a wireless internet router, all from Comcast. I’m paying out the nose in rental fees! I want to try getting my own cable modems and OOMA. My question is, is there an option for replacing those little bitty $3 boxes without spending a lot per box?

  • Messenger says:

    Aren’t you forgetting the telephone /VOIP/. The correct cable modem should be a telephone(VOIP) / cable / Internet(WAN) modem. Most of the modems you can buy don’t have Voice over IP.

    Do you know of any?

    I am just a messenger…

  • Jason says:

    Great tips, G.E., but after purchasing a Motorola SB6141, I came up to a problem.

    The modem itself works fine for the internet and Comcast has the MAC ID and other info on file. However, I also have phone service through Comcast and the previous modem I was renting from them had my phone cable (in addition to the ethernet cable) connecting to the back of the modem. My new Motorola modem doesn’t HAVE a connection for phone cables, only one for the ethernet cable. And now, I can’t get a dial-tone on any of my landline phones.

    I called Comcast and they said that I need an “eMTA” modem in order to reconnect my phone and get my phone service to work again. I’ve never heard of this. Do you have any recommendations or solutions to this problem? I need my phone and right now, aren’t interested in dumping my Comcast landline. I just want it to work again!

    Any help would be appreciated!


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