DOES NOT WORK ON COMCAST & ARRIS SUPPORT IS A SCAM
342122
I had this modem for 3 years on WOW ISP. After switching to Comcast (xfinity) it no longer worked. Spent 12 hours with comcast and arris support trying to figure out why. Even tough it was listed as compatible on comcast and had worked fine that morning on WOW, both ended up throwing in the towel and telling to buy new... and the arris online chat rep passed me off so fast to the phone support (which charges you whether or not they fix your issue) that I won't be from Arris ever again. The comcast people at lest didn't charge me and were willing to listen to my problem.
1261265
I bought this router/modem to handle my high speed through Comcast.  Router started off fine but over the next month all our devices kept dropping connections.  I called Arris support line several times and they kept giving me the same fix.  It would fix for a day or two and then right back to dropping connection.  I would unplug and call support.  Support team never tried anything else.  I finally gave up and bought a new modem and separate router neither of them Arris.  Everything works great and connection never drops.  I would not recommend this product, I just spent $90 to drop in the trash.
3238395
I purchased this unit new in April 2015. I purchased it to replace my original Arris 822 modem on my Comcast network. I was tired of paying the modem rental fees!  This unit has had problems with Internet traffic since day 1. First, Comcast was able to provision the modem for data, but not voice. It took them over 14 hours to get my Comcast phone number provisioned on the unit, and then, when they said it was complete, I could only receive calls, not make calls!  Finally they corrected the Comcast voice issue. However, call quality has been poor. It sounds like someone is talking from underwater, even though I have tested the unit with a several quality phones connected directly to the modem. The more troubling problem is that the modem needs to be reset frequently. Comcast ran new line to my house and also replaced the line that runs from the junction box to the room where I have the modem and Wifi router installed.  Comcast reported that they are receiving a lot of "noise bursts" on my line, even though new cable has been run. They now suspect that the modem is the fault.  What is really bizarre is that my previous Comcast modem was an Arris 822 (same model) and NEVER had any problems with the service. Of course, Comcast is recommending that I RENT a modem from them again.  Regardless, I would not recommend this modem to anyone with Comcast internet and voice.  It isn't worth it.
1893984
Product did not work even though it was refurbished, needed my own box to stop paying comcast fees very disappointed product said it can replace comcast modem that wasn't true
4056298
Refurbished modems, Comcast won't be able to add them to your account because they were previously added to other peoples account. I strongly discourage you getting this product, you will not be able to use them
4029320
I bought this item in the hopes of reducing my mother's Comcast bill since SS doesn't give her much income and her senior home is exclusive to Comcast so she's pretty much stuck with that sucky service. I thought this was an awesome deal and was so happy that I could help her out. So I go and set everything up, box up the rented router and call Comcast to activate this one...
Imagine my disappointment and frustration and ANGER when they tell me that this box CAN NOT be activated because it's at the end of its life!! I felt like such an idiot for believing this was actually a good deal!! Thanks for making a fool out of me! Definitely sending this piece of junk back and getting my money back!!!!!!!
4364121
Okay so I have had this modem for over 6 months and as soon as I recoup my purchase cost from rental fees saved this is going in the trash. So for starters I live out in the county and have fairly good separation between homes and nearly 5 times a week to 5 times a day I have to manually switch channels because the Arris always yields to weaker traffic. (As defined by the Arris technical support team that I need to switch manually since Auto channel is not functional in the presence of other WiFi) and also told me it was my cable companies fault that this was occurring because of signal strength even though coincidentally my 6 year old rental modem never once dropped out for this same issue. But I digress and had the cable company install a brand spanking new drop from pole to home and re-coaxed to the modem and guess what? waste of time

Modem still does the exact same thing. WiFi strength fails in my home at approx 25 feet from modem but oddly and frustratingly enough has no problem drawing in WiFi from 300 feet or more away to knock me offline. Did I mention my crappy 6 year old rental never dropped.  And so the coup de grace is my cable company just upgraded us to 100 Mbps service for no upcharge and guess what, yup modem will not produce more that 66 on wireless but 112 Mbps on wired. 2 more months and on to a competitor

Waste of Money
448944
Could not get it to work. Poor customer support called them 10 times and half the time I was talking to someone in India. The customer support from frontier was even worse,  called them 10 times as well.  Finally had to throw in the towel and send it back to amazon. I really hate to let comcast back into my home for any reason, but after this ordeal I don't have any other choice other than satellite Internet. This much I do know frontier is gone and so is my tp link TD-8980
3347285
I had a heck of a time getting this set up. First, I downloaded the user manual before doing anything. (Netgear doesn't include it in the box, but that's okay with me.) There is also a Quick Start guide. I chose to follow the more extensive user manual, which was a mistake. The user manual instructs you to log on to your ISP's website (they include a table with all major ISPs) to activate the modem once you've hooked everything up. Everything worked well (internet and telephone) once I hooked everything up, and I was able to log onto Comcast Xfinity's activation website. It seemed to work, but I was never prompted to provide the modem's model number and MAC addresses. This worried me, per some reviews here, that my internet and phone would go down soon if I didn't give this Comcast.

The Quick Start guide didn't give any website addresses, but only said call Comcast to activate it. So, I called, and the automated system asked if I wanted to activate a device. I said "yes," and the system sent a reset to my modem. Nothing worked after that. Then I called the dreaded customer support.

After almost 90 minutes, the CS rep got my internet back up, but the not the telephone. The rep finally told me he was escalating the issue to "Level 3," and that I'd hear back from them within 24 hours. What, go without my phone for 24 hours, and no guarantee that they'd get it working? Nope, no way.

I told the rep to deactivate the CM500V, and I hooked back up my Comcast/Xfinity modem/telephone tower (the thing is really big) to make sure things were back to normal, but decided to try one more time. The second time I followed the instructions in the Quick Start guide rather than the user manual.

I first reset the modem to factory settings just in case something had been modified that I wasn't aware of. Next, I started everything up from scratch, got the internet and phone service working, but did not log onto Comcast's activation website. Instead, per the instructions, I called Comcast to activate it.

The tech rep told me that it was already set up. I asked him if he had the hardware's MAC addresses and model number, and he said yes. I asked him how they got it, and he said the system picked them up automatically. It has been working like a charm. I hooked it up to a new router with no problems.

Now that I'm up and running, I get much higher speeds that I was getting with the Comcast equipment, and I suspect that some of intermittent problems I've had with my internet are resolved now (such as being inexplicably disconnected form some web sites, sudden slowdowns, etc.). I have better control over my technology now and am saving $11 a month on top of that.

It appears (and I use that word with caution) that Comcast has actually streamlined the setup of this modem, and possibly others, by automatically picking up the hardware info. In the end, I'm very happy, and love my new Netgear modem.
3494625
I have had this modem for 2-3 years now, foolishly renting it from Comcast for $10 per month.  While I would have like to get a new, more expensive model - preferably a modem/router combination - some of the prices are high and this model - the Arris CM820A - is really good and has caused me no issues or hassles these past years.  I pay for the 100 mbps internet package which works great for mobile streaming sports; 25 mbps caused a lot of freezing and found it useless even when only having 2-3 devices connected.

I received my refurbished Arris CM820A modem today and my customer service call and installation experience with Comcast went well.

Here is the process, briefly:  1) Comcast customer service first checks if the modem has an End of Life restriction, meaning if Comcast still recognizes the modem brand and model as an accepted modem Comcast accepts for use; at this time, Comcast does accept and uses the Arris CM820A; 2) Comcast customer service inserts the CMAC code (a combination of numbers and letters found on the back of the modem) into their system to check if the modem is coupled with someone else's account (if it is attached to someone's else's account, it's a no go).

After that, Comcast will couple your new modem with your account and send a connection signal, which may take 2-3 minutes as the modem's orange and green lights blink on and off as it cycles through its start-up.  Be patient, my modem blinked and cycled through close to five minutes.  Once all the green lights are on, browse through different pages on your browser to make sure your internet connection is working.  I would also suggest you google "speed test" and check to make sure you are getting the speed you pay for, i.e. 25, 100, or 200 mbps/sec, etc.

Don't forget to return to Comcast the modem you were renting!

UPDATE: the modem stopped working.  There was an outage for about half an hour, but the modem was plugged into a surge protector.
1798602
Product was defective. Didnt work at all. Called ARRIS directly and they first tried to blame the cable company, then admitted the product was defective after finally listening that the only light on was a USB light (also tried to suggest my outlet was broken). Well, I guess if its cheap, its prob too good to be true but Im paying for internet while now waiting for another modem...that hopefully won't also be defective...
1212283
Horrible ! Do not by these refurbished modems. Mine had a mac address that wasn't valid. Both Comcast and netgear support could not fix the issue. Mainly being that Comcast has to use the mac address on the router and the mac address in the software was different. They explained to me that I bought stolen router. Comcast rep told me these routers are crap anyways and constantly get swapped out.
423853
I've been working on setting this up for hours and nothing works as they indicate it will. They boast about the ease of setup but it seems most of the reviews I've seen indicates the opposite.  No tech support after 7pm. They are closed when most people find time to set this type of equipment up.  After work and the kids are in bed. No prior warning of the issues with X1 Comcast and using the Slingbox 500.  Poor audio and it doesn't pass through to my home TV.  They sell the 500 for close to $300.00 and then charge $14.99 for the application to use on an IOS device.  There isn't an email address to contact anyone in reference to tech support or customer support.  I've set up a home IP video surveillance system, my home network with an NAS, I consider myself pretty handy when it comes to configuring home electronics but this is the most unfriendly device I've ever had to deal with.  Don't torture yourself, I would not recommend this product.
3788077
Coworker talked about buying Roku...so, I thought I'd try it.

I called ROKU BY PHONE, told customer service what kind of TVs I have and
My Internet service is ATT UVERSE.

They told me to buy 2 HD cables for $10 each along with the 2 ROKUs one for each TV.

I got them in 8 days.

I called their tech support to help me with set up.

2 hours on the phone trying again and again but the device would not read my Internet modem.

Then, they give me PRIMARY AND SECONDARY DNS numbers and tell to
Call ATT and have them change my DNS numbers.

I call ATT . I don't have a tech support plan, so they charge me $50 to speak to ATT TECH SUPPORT in India.

Then after 30 more minutes, the guy tells me that my DNS numbers are assigned to my modem and can NEVER be change.

3 hrs in total wasted.  Had to send COUNTLESS emails to ROKU begging for a return address.

REpackaged devices, paid for return postage plus the cost of ATT service and now I have to wait more than 10 days to get them off my credit card.

WHY THE HELL didn't they just tell me it wouldn't work with my system when I called them before placing the order?

I live in the city in FL and not some remote place.

No clue why it wouldn't work, and they don't know either.

WASTE OF MY TIME AND MONEY.
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3430567
I have worked with Time Warner and Arris support and have not been able to get this modem to stop dropping out. When it works it works well but then it drops out for several minutes (up to 10 minutes)  every hour or so.  Arris said the cable signal was too good (hot) so I purchased and installed an attenuator from Amazon to cut down the signal strength.  That did not solve the issue.  Time Warner said the signal was very good with no issues.  Now the 30 day return policy has expired and not eligible for return.  Just be aware and purchase with knowledge. This one is on the Time Warner compatible list.  It might just be a bad unit but how can I tell.  I purchased it because it looked to be the best available (at least the most expensive).  There are no firmware updates available as of Aug 2016. Maybe it is just too new and not proven.  I am only on a Time Warner 20 meg plan (Turbo) and receive 22-23 meg most of the time when the device works, so excess speed is not the issue. The maximum plan Time Warner offers in my area is 30 meg.  With 50 meg available in some areas near me. I guess I will just throw this one in the trash and take my lumps and be done with Arris and all the ridicule from my wife and son that the internet is down again.
As a test, I went to the Time Warner office and picked up one of their Arris SBG6580 wireless modems and swapped it out with my purchased Arris SGB6900AC.  The rented SBG6580 works like a champ so the 6900 I have must have issues. No wiring changes were made and no Time Warner tech came by so the issue must be with the SBG6900AC.
1828212
Terrible product and support.  Product worked intermittently with our Comcast cable provider.  Comcast service technician had to install the Tivo after I tried unsuccessfully to install for 3 days.  Error messages were "weak or no signal" and "Tivo can not connect to your cable provider.  Call Cable provider to resolve."  The Comcast echnician was able to get Tivo working intermittently but errors returned.  Tivo tech support said my problem was a failing TV.  Funny, when the Comcast technician replaced the Tivo with a Comcast controller, everything worked as expected.  Now I have to struggle to get refunds on the Tivo controller and service agreements.  Plus I need to schedule a new Comcast technician service call to bring a Comcast controller and install it to replaced the failed Tivo.  I'm expecting $500 in Comcast fees for this disastrous and expensive Tivo experience.
4450911
ARRIS SBG7580AC will NOT work with Optimum Online cable service, I bought this stupidly believing the cable websites information that most any DOCSIS 3.0 modem will work. This is not the case. For anyone that finds this review the best "approved" modem OOL supports is the ARRIS TM 1602-g which of course cannot be found any where accept directly from arris or OOL stores.