Review: Arris TM822G DOCSIS 3.0 8×4 Ultra-High Speed Telephony Cable Modem

Arris TM822 ReviewTo lease, or not to lease. That’s the question for anyone who gets their high speed Internet through Comcast Xfinity. Literally millions of Comcast customers (over 18MM, to be exact) are paying an extra $7 per month to rent a modem from the cable company, and if you’re unsure whether or not you’re one of them, then I’d be willing to bet you $7 that you are.

Admittedly, there are some benefits to coughing up the monthly $7 fee to Comcast. First, if your modem breaks, they’ll replace it for free. Second, if your modem becomes outdated, they’ll swap it our for an upgraded one for free. So, if those two benefits are worth $7 a month to you, then go ahead and keep on renting.

Me? I’m a cheapskate frugal. Thinking back on my cable modem ownership (and checking my Comcast account), it seems I’ve owned three cable modems over the past 12 years. My first was a Thompson RCA DCM 235 DOCSIS 1.0. The term “DOCSIS” is an acronym that stands for “Data Over Cable Service Interface Specification,” which simply refers to the type of technology used to send Internet “stuff” over cable TV lines. My original first-generation cable modem worked fine for years, but when Comcast started supporting the DOCSIS 2.0 technology on their network (which allowed for faster and more reliable Internet service), I upgraded my modem to a Linksys BEFCMU10 v4 to take advantage. I used the Linksys without issues until April 2012, when Comcast called to inform me that in order to take advantage of their most recent network upgrades, I’d need to upgrade to a newer DOCSIS 3.0 modem. That’s also when I decided to ditch my local telephone provider and switch my phones over to Comcast Voice, meaning I’d need to replace my cable modem anyway for one that supported telephone in addition to Internet. So, after reading some online reviews about the latest and greatest cable modems, and talking to some Comcast technicians, I purchased an Arris TM822G on Amazon for $59.95 (with free shipping and no tax).

Arris TM822G Cable and Telephony Modem

Arris TM822G Cable and Telephony Modem

Over the past 12 years, on average, I paid no more than $70 for each of the three cable modems I purchased. So if I take 12 months times $7 times 12 years, that equals $1,008 — and if I subtract $210 (3 modems times $70 each), that means I’ve saved close to $800 in modem rental fees over the past 12 years. And since each cable modem has paid for itself in less than a year, and none of them have ever broken before I’ve needed to upgrade them voluntarily, I still believe that purchasing your own modem is the right way to go.

I would have written a review on this modem back in April 2012, when I first bought it. However, I forgot one very important step when purchasing the TM822G:

I neglected to check Comcast’s Approved Devices List to verify that the TM822G was on the list.

In my defense, I never even imagined it wouldn’t be. Arris manufactures the modems that Comcast leases to its customers, so it never occurred to me that they wouldn’t support one of Arris’ most highly rated, fastest, and feature-rich modems — especially when a Comcast tech specifically recommended the TM822G to me as (and I quote) “the best.” But, to my dismay, the TM822G wasn’t supported by Comcast, so in order to switch over to their voice service last April (which saved me a bunch on my monthly phone bill), I was forced to pay the $7 monthly fee to rent an Arris TG862G instead, until they eventually got around to including the TM822G on their approved devices list. Finally, in September 2012, Comcast announced support for the TM822G, so I was able to return the rented modem and start using my own, which had been sitting… sad, lonely, unused, and unloved… in a box under my desk for months.

Without turning this post into a rant, suffice it to say that switching from the leased modem to my owned one didn’t go smoothly. It took two full days of constant phone calls and online chats with Comcast tech support, some posts in their support forum, and an in-person visit to a Comcast store, to finally get it all working properly. But, once all the wrinkles were ironed out, I was able to focus on an honest evaluation of the Arris’ TM822G modem without Comcast’s crappy customer service clouding the issue.

Quite simply, the TM822G is nothing more than a cable / EMTA (phone) modem. It’s not a wireless access point, it’s not a router, it’s not a gateway… which is exactly what I want in a cable modem. Keeping my wireless router and access points separate from my cable modem gives me far more flexibility over my network setup, especially since I use third-party firmware (such as DD-WRT and Tomato) on my WiFi routers and access points. And even though history has shown that I haven’t needed to do so often, having it separate also allows me to swap out the modem as necessary, without losing all the configuration options on my router. That’s exactly what I did when putting the TM822G into service. It took less than 5 minutes to physically disconnect the old modem and hook up the new one, without the need to take my internal network offline.

Speaking of connections, the Arris TM822G keeps things simple, with only five connections on the back: a power cable connector, an RJ-45 Ethernet port to connect to your router, a coax “F” connector to connect to the cable company, and two RJ-11 phone jacks to connect up to two telephone lines (technically, it’s actually one RJ-14 and one RJ-11). There’s also a reset button (which you’ll need a paper clip to press when the 14th Comcast support agent of the day asks you to press it, over… and over.. and over…)

The TM822G only has one available accessory: a backup battery to keep the modem (and your phone lines) running run the event of a power outage. I decided not to install it, however, for two reasons. First, I already plug all my network devices into a large battery backup unit, which only has to run long enough to wait for the generator to kick on. Second, I connect my modem, router, and main switch to that battery backup unit via a remote control Baytech power strip, which allows me to kill and restore power to any of those devices remotely — including via a Linux shell script that pings a number of sites to see whether everything’s working ok, and then automagically logs into the Baytech and reboots the modem and router if I’m offline (which fixes the issue more than 90% of the time).

Where the TM822G shines, as would be appreciated by former First Lady Eleanor Roosevelt, is “speed… hot, nasty, bad-a$$ speed.” It supports up to 8 bonded channels for downstream connections (providing for a theoretical max download speed of 343 Mbps), and 4 bonded channels for upstream connections (yielding a theoretical max upload speed of 122 Mbps). In actuality, with Comcast’s top tier of residential service, I get around 35 Mbps down, and 5 Mbps up. UPDATE! Comcast upped their speed for my service tier in April 2013, so now I’m getting just under 50 MBps down and almost 12 Mbps up:

That’s at least 10 25 Mbps more “down” than I was getting with my old DOCSIS 2.0 modem, and a couple more double the speed “up,” to boot. That’s still comfortably within the expansive capabilities of the TM822G, so if (when?) Comcast eventually decides to cough up more bandwidth (like they did in April), the TM822G will be able to handle it.

In addition to raw speed, the TM822G also shines when it comes to specifications compliance. It supports IPv6, PacketCable 1.0 and 1.5, SIP (according to RFC2161), encoded speech codecs G.711, G.726, G.728, and G.729E, and has T.38 fax relay support. If all that makes your eyes glaze over, just take my word that the TM822G has all the “goodies” to ensure that it won’t be outdated anytime soon (you can check the spec sheet for more geeky awesomeness). And to get all that for $59.95 is a steal.

Which brings me to the only bad news of this review:

You can’t buy an Arris TM822G for $59.95 any more.

I suppose it’s the law of supply and demand. When the TM822G wasn’t supported by Comcast, there was little demand, meaning retailers had to sell them for cheap if they wanted to sell them at all. But now that it is on Comcast’s list, and given that it’s the fastest, most highly rated, and one of the most reliable cable modems in a number of independent tests, the Amazon price is now closer to $190 and the eBay price is around $160. Even used, they’re going for between $80-$100 on eBay.

Warning: if you decide to buy one used, be very careful. If it was already provisioned (or set up) on the Comcast network by another customer, I’ve read horror stories online about trying to get them re-provisioned for your account.

Of course, this price jump isn’t Arris’ fault, but it does extend the break-even point for your $7 per month potential savings, which is something to keep in mind as you make that decision.

My decision is easy. At the price I paid for it back in April, and even at the price you’d probably have to pay for it today, this cable modem is a winner. So if you’re ready to stop coughing up $7 a month to Cabletown Comcast, the Arris TM822G is almost certainly going to last more than long enough to get you to a break even point.

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  1. Wow, after reading this, I can’t figure out what you are, I guess the best I can come up with is renaissance man :). This next quoted part is AWESOME, i have been in IT 15 years and I never think of it, SHAME on me, but on my list to do ASAP, hopefully FAR FEWER tech support calls from home when the “internet isn’t’ working” :). I have been writing Perl/KSH/TCL for almost 20, this sounds like fun!!

    Thanks for the review too, although I despise Comcast, I am a happy U-Verse customer, with their top tier service(18/3, and that is exactly what I get, ALWAYS, I have a bandwidth monitoring script because of all of the issues I had in the past with Comcast and Time Warner screwing me on bandwidth, and I always got credit back when I showed them how crappy my bandwidth really was half the time, why should I pay 100% of their top tier fee when I am not getting the bandwidth?), although I live in North KCMO, the first city that Google picked(we won some kind of contest) to completely run a private fiber network with Gb speeds and cable TV (I am thinking about moving to get to their phase I area :D): $120/mo for 1Gb (synchronous up/down I think!!) AND ALL cable TV??? Forgeddaboutit!

    This rocks:
    Second, I connect my modem, router, and main switch to that battery backup unit via a remote control Baytech power strip, which allows me to kill and restore power to any of those devices remotely — including via a Linux shell script that pings a number of sites to see whether everything’s working ok, and then automagically logs into the Baytech and reboots the modem and router if I’m offline (which fixes the issue more than 90% of the time)

    • Hi Mike, I picked up the new ARRIS TG862 from Comcast Store
      on Thursday. Am no guru. Have Comcast Triple Play. They took my
      existing modem which worked fine and gave me this new one. Well,
      after 2 days of trying unsuccessfully to get any phone dial tone or
      voice on my land line, I gave up. Read all the negative stuff about
      this company online. Am without any phone. Notice if anybody comes
      over with a cell phone, it goofs up their cell phone. I have no
      cell, just the landline, tv and internet service. Will return to CC
      store and return their ARRIS TG862 and hope to get my old modem
      back. Does anybody know why this modem killed my phone service? No
      dial tone, no sound. Cannot call out, people cannot call in. This
      is dangerous; what if emergency? Thanks for listening to my rant.
      June Helen

  2. P.S. with U-Verse I am using their VOIP, but I have a brand new Ooma Telo and Ooma Linx (got on sale from Costco for $130 for both!) with two line capability (home and office lines) that I got the family for xmas, should save me $25/mo while I get 2 lines instead of my current one… and has AWESOME features and integration with Google Voice(VM transcription, access to VMs from the inet and sent to your cell, and so much more, oh yeah), pretty excited!

  3. Comcast indicates that it supports the TM822G (NCS) and TM822G (NIS), but I am unsure about the significance of the last three letters. The modem that I currently am leasing is a TM722G/CT. The modem sold on Amazon is listed as a TM822G/NA. Does that mean the one available through Amazon is not supported by Comcast?

    • The one sold through Amazon is the exact one I purchased, and it IS supported. I don’t believe the NCS and NIS letters are specific to the device, as I can find no reference to those model numbers and letters together, other than on the Comcast page. I believe Comcast is just staying that modem support NCS and NIS technologies (NCS is a variation of the Media Gateway Control Protocol (MGCP) signaling method to control endpoints, for example).

      • Thanks, I’ll order one, relax, have several drinks, then begin the process of getting Comcast to recognize it.

        • Yeah – check out the wiki entry for your router of choice at Be sure to follow the instructions closely, as installing the wrong version of the firmware could render your router useless. Also keep in mind that only the first version of the Cisco/Linksys E4200 is flashable. The E4200 V2 is not. Although, this is a great router even WITH the stock firmware, and there’s no need to change it unless you feel like tinkering. :)

          • Well, I took a look at that wiki entry and I got got of scared to tell you the truth. I’m afraid that I might end up damaging my router. Have you posted any youtube video on how to flash the Cisco E4200? And do you have a condensed step by step instructions that was created by you. Please help. By the way, both the Arris TM822G modem and the cisco E4200 router are great products.

  4. What do you have to do to get the Modem to work with Comcast? Did you have to take it to their office to have it addressed to your account or just plug it in and call them? Thinking about buying (don’t like paying $7 a month) but not sure how complicated it will be to set up. (I use my own wireless router). Thanks for any help you can provide.

  5. not much more than a rant of costs, then a note that most of the rant no longer applied.
    I was looking for a comparison from your old, or any other device.

    • Comparison is easy. My old device (a Linksys) was DOCSIS 2.0. This new Arris is a DOCSIS 3.0. No matter how much I may have liked my old modem (and I did like it), it would never be as fast on Comcast’s upgraded system as a DOCSIS 3.0. My Linksys didn’t support telephone service, this does. That’s pretty much it. :)

  6. I’m so bummed!, price on this unit from amazon is now $160!
    after spending all day on phone w/ C.Cast, and researching
    online—then finding this great info! (thanks Steve!!)— I
    thought I was onto something I could commit to…Wrong :(….back
    to the drawing board….unless other model?

  7. Steve, You could be my twin, because you were where I am
    now. I’ve been on the phone with COMCAST for nearly 2 hours trying
    to switch my phone service from AT&T to COMCAST. The newest
    wrinkle – they said they are going to charge me $33 for a
    technician to come out to wire something. I want to be able to use
    my old land line handsets on the new phone service. Is that what
    you did and did you have to have someone come out to re-wire
    something with the old phone jacks?

    • Lorraine, I changed from AT&T to COMCAST. Be sure you plug your telephone line into jack T1. This is the left jack not the right one. The right jack is for a second telephone like a fax machine and requires a special setup from COMCAST. My problem occurred regarding my GE burglar alarm. COMCAST reversed the polarity of the telephone connections. This did not affect my existing telephones, only the GE unit. I had to pay $130 for the alarm company to come out and switch the wires to the alarm unit. Other than than I just plugged the T1 jack into a wall telephone jack just like AT&T. Hope this helps.

  8. Hey Steve,

    I have the ArrisTM822 and using Comcast as well. We’ve had it for a year or so. My problem is that randomly, but pretty predictably every morning, the Arris seems to shut down, lose signal, whatever you want to call it (I’ve never actually seen it reboot and turn off and then back on so I’m not really sure what happens. The net effect is that we lose internet and phone.) It will eventually come back up on it’s own but not quickly. (In the morning when this happens it’s actually a good alarm clock as my girls always walk out of their rooms and yell, “Wireless is out” ;-)

    Anyway, any thoughts on what might be going on? Do I just have a bum modem and need a new one? FWIW I rent this from Comcast and it does NOT have a back up battery.



    • Hi, Dave. Could be a bad modem, or could be bad connection. In either case, it’s Comcast’s responsibility to address, since you’re renting the modem from them. Get your money’s worth by calling their customer service dept (1-800-COMCAST) and have them send you a replacement, or service the line.

  9. Hi Steve,

    Your review motivated me to buy a used TM822G. I got it provisioned today which took about 3 hours on the phone and talking to about six Comcast staff! The reason was a dropped call and some Comcast staff not doing their job carefully in noting down the serial number, CMAC address, etc. Now it is working. Thank you for the detailed description.

  10. Hey Steve~ I too wanted to purchase my own Modem to get away from paying Comcast the $7 a mo….NOW, $8 a mo.!!! Needing a Telephony type modem….coulda..shoulda bought one a couple years ago for around $90 from Radio Shack…and YES it had telephony! Now there outrageous $250 and more!**** Currently: After some techno-issues with Comcast they told me I should upgrade to a Gateway, they sent me one along with a box to return my current Modem; an Arris model: TM502G…telling me I would most likely be experiencing more problems “After the first of the year”. The gateway they sent me is an ‘Xfinity’ Gateway with (I think) model #TC8305C. What I’m not sure about, is DO I Really Need to switch these out or not? or does Comcast just want my old modem back to update its internal hardware and sell on Amazon for $300!!!!

  11. I just went through this process, successfully, but with a lot of cursing directed at Comcast.

    I decided to purchase a modem right after paying my last cable bill, which was quite high. International long distance? Texting? No—a call to Comcast uncovered several rate hikes, including an increase to $8/mo for rent on the old cable modem.

    Step 1 was to threaten to leave for Verizon and drive the services and costs down to the bare minimum. That saved almost a third from the monthly bill.

    Step 2 was to purchase the Arris TM822. At this point, it was less about saving money than it was about not giving Comcast even an extra penny. I purchased the TM822A for around $70. The TM822A is identical to the TM822G without a battery. I also use a hefty UPS for my LAN, so the puny battery in the G isn’t of any use to me.

    Step 3 was to get Comcast to provision TM822, and this was a nightmare. The self-activation process didn’t work. Self-activation should be your first priority, but don’t be too optimistic. I spent almost a week of daily phone calls asking Comcast to fix it. None of the tier 1 techs could get it provisioned, and Comcast failed to call me back within 24–72 hours with tier 2 support, as they said they would. My strategy shifted to issuing daily complaints that my phone and internet didn’t work, which was true as long as my modem was attached. Finally, Comcast sent tech support to my home, and with the right phone calls the home techs arranged to get the TM822A provisioned and running in less than thirty minutes.

    Everything is working great now, and wget says that the TM822 downloads at the current 25 Mbps Comcast limit.

  12. Hi hopefully you still comment on this post. I’m tired of paying $8 (yes that’s what they charge now) for my modem and want to buy one. So I’m reviewing comcast list to see which one to buy. I’m not a tech person by any means so this stuff confuses me but I do want to buy one that will work, so I’m trying to review the different ones they have listed. I noticed you used the Arris TM862G and wanted to know what you thought of it. Would you recommend buy a modem/router combo? I don’t need the modem to work on telephone lines (unless of course it’s needed for my internet). And if I were to purchase the modem you have and buy separate router what is “flash” mean? I’m so confused, any suggestion you can part would be much appreciated.

  13. I was reading your post and wanted to just say that the Battery for this device would not provide Data during a power failure it is solely for eMTA purposes to provide Voice/E911 service during a power outage.

  14. So I just jumped through all the hoops to “Own” a modem and get it activated. I purchased it from eBay, it was the Arris TM822. As soon as it arrived I plugged it in and got everything up and running without difficulty. I thought everything was good. I waited a few days to make sure everything continues to run and returned the rented modem to my local Comcast store. The customer service lady was unable to remove it from my account because they did not have my new serial number. I was instructed to call when I returned home and it would be removed from my account.

    This is when things got tricky. I spoke with several people at Comcast that couldn’t help me. Then I connected to the telephone department and the man told me that it is impossible to own a modem and continue to have Comcast telephone service. I explained that it was the Comcast website that directed me toward which modem to buy. I also tried to explain to him that I was talking to him using the phone connected to the modem that he assured me would not work, he didn’t like that response. I decided not to argue and just call back, which is exactly what I did. I spoke with a woman in the billing department, she was very helpful, when she couldn’t change my account she contacted someone in the telephone department and we were on a 3-way call. I explained the situation again, and after about 15-20 minutes the issue was resolved and I am told that the $8/month rental fee has been removed.

    I have not gotten a bill yet to confirm, but based on the conversation I believe that the issue has been resolved.

    I will repost if I have any addition problems or updates.

  15. I have Comcast Triple play- internet, cable, phone. I’m sick of their escalating prices and the Comcast Tech guy suggested I purchase my own modem specifically the Arris TM722G. I found the Region Supply, LLC, on line which seems to be a well rated business to purchase a modem from. They sell both the TM722G and TM822G. I see my rented modem from Comcast is the TM822G- so why would the tech guy have specifically told me to purchase the TM722G? Which should I buy? And should I be concerned about all the posts reporting what a nightmare it was to get their purchased modem recognized by Comcast? I’m afraid I don’t have the stomach to spend time and numerous phone calls to get my modem working. HELP?!

    • I purchased a TM822G online, set up was easy and it worked fine. The hassle came when I tried to get them to remove the lease rental fee from my old equipment, I was told initially that it was no problem, then when I actually called to remove it the man said that is impossible and if I was using my own modem it would work for a while then it would be disabled by comcast. I called back once again and they did take care of it, I had to work with someone in billing and someone in the telephone department to make it work. It was a hassle but in the end I am glad I decided to purchase the modem.