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Item#: 9SIA0AJ35M9325

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  • Overview
  • Specifications
  • Warranty & Returns
  • Reviews

Learn more about the Netgear Inc. CMD31T-100NAS




Cable Modem
Ethernet Port
Cable Interface
One (1) LAN Gigabit Ethernet port
One (1) WAN Female F connector
Max Transmission Rate
150 Mbps


For high-speed cable Internet access

Works with major cable ISPs

Save money-no monthly equipment charges

Designed to meet DOCSIS 3.0 specifications and backward compatible with DOCSIS 2.0 networks

IPv6 Next Generation Internet addressing support

Gigabit Ethernet port with auto-sensing technology

System Requirements:
Cable Broadband Internet service
Microsoft Windows 7, Vista, XP, 2000, Mac OS, or other operating systems running a TCP/IP network
Microsoft Internet Explorer 5.0, Firefox 2.0, Safari 1.4, or Google Chrome 11.0 browsers or higher

CD-less installation.


Package Contents
High Speed Cable Modem - DOCSIS 3.0 (CMD31T)
Ethernet cable
Power adapter, localized to country of sale
Warranty, Returns, And Additional Information
  • Warranty
  • Limited Warranty period (parts): 1 year
  • Limited Warranty period (labor): 1 year
  • Read full details

Customer Reviews of the Netgear Inc. CMD31T-100NAS

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2 out of 5 eggsDoesn't work with Cox Premier Svc

Pros: DOCSIS 3.0. Gigabit Ethernet port. Supports speeds up to 150 Mbps.

Cons: Unfortunately, I was never able to get this modem working on the Cox network. I am not sure if it is a faulty modem, or if it is no longer compatible with the recent changes Cox has made to their network to accommodate the new speed standards, especially with the roll out of their GigaBlast service in the Phoenix area (where I live).

Other Thoughts: When I plug the coax cable into the modem, it never comes ready, and the ISP (Cox) can not see it. It is not possible to provision and register the modem. There was some confusion at Cox as to whether this modem is on their approved list, with some lists showing it and others not showing it. In any case, this is an older modem that Netgear tells me is being phased out. I upgraded to a CM600 which is working great. See my review for more details if you are interested.
Bottom line is that this modem is being phased out by Netgear so you will probably not see it in the stores anyway. Stick the the CM600 which is future proof right up to Gigabit speeds.

For those interested, this is what was contained in the error log:
Time Not Established Error (4) ToD request sent- No Response received;CM-MAC=28:c6:8e:31:4b:...
Time Not Established Warning (5) MDD message timeout;CM-MAC=28:c6:8e:31:4b:80;CMTS-MAC=6c:41:6...
Time Not Established Critical (3) No Ranging Response received - T3 time-out;CM-MAC=28:c6:8e:31...
Mon Mar 21 08:17:09 2016 Critical (3) Received Response to Broadcast Maintenance Request, But no Un...
Time Not Established Warning (5) MDD message timeout;CM-MAC=28:c6:8e:31:4b:80;CMTS-MAC=6c:41:6...
Tue Mar 22 16:10:49 2016 Critical (3) Received Response to Broadcast Maintenance Request, But no Un...
Time Not Established Warning (5) MDD message timeout;CM-MAC=28:c6:8e:31:4b:80;CMTS-MAC=6c:41:6...
Tue Mar 22 16:32:42 2016 Critical (3) Received Response to Broadcast Maintenance Request, But no Un...
Tue Mar 22 16:32:46 2016 Critical (3) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:...
Time Not Established Warning (5) MDD message timeout;CM-MAC=28:c6:8e:31:4b:80;CMTS-MAC=6c:41:6...
Tue Apr 5 09:02:49 2016 Critical (3) Received Response to Broadcast Maintenance Request, But no Un...

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  • Anonymous
  • 8/14/2015 1:28:10 PM
  • Ownership: more than 1 year

1 out of 5 eggsDo NOT buy this product

Pros: Easy to set up.

Cons: Everything else.

Other Thoughts: I bought this modem along with an ASUS router to replace the leased equipment. Never before have I hated a network device as much as Netgear modem. I have to reboot this modem at least twice a week (usually more) and it constantly drops connection to Comcast.

Called Comcast support about this issue and they basically told me to buy a new modem. I have read numerous horror stories about this modem from other people online having the same issues.

Funny enough, I saw this same modem I paid $90 for brand new for $3 at a thrift store the other day. Shows how horrible this product is. Do yourself a favor and buy a Motorola modem.

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5 out of 5 eggsWorking Cable Modem

Pros: -DOCSIS 3.0
-Compatible with Comcast, Time Warner, Charter, Cox, Cablevision, and more.

Easy installation. Unhooked my old modem, hooked this one up, waited 15 minutes, called my internet provider and gave them the model # and MAC address. 15 minutes later I had internet access. Speeds were on par with the speeds of the modem I replaced. (NOTE: I'm currently on one of the slower/cheaper internet plans.)

Cons: None.

Other Thoughts: There's not a whole lot to say about this device. It's a DOCSIS 3.0 cable modem which means you should get all the benefit of DOCSIS 3.0 without having to pay your provider their monthly rental fee. I note there are a number of comments about devices dying. I had no problems in the short time I used this. If you're looking for a modern DOCSIS 3.0 modem I see no reason not to consider this. Just keep in mind it's a modem only, most of you will still need/want a wireless router to plug into this - though you likely already have a separate modem and router.

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  • Cyrille F.
  • 4/19/2015 9:06:07 PM
  • Ownership: 1 week to 1 month
  • Verified Owner

1 out of 5 eggsNetgear CMD31T stopped working after 6 months

Pros: When working, my speeds with Cox internet increased.

Cons: Had minor issues with having to reset the modem every other week or so. Then it was every couple of days to every day. Now, the modem won't even power on.

Other Thoughts: I sent an email to to request a RMA. If they don't assist, I will not buy another Netgear product. Other Netgear products do work well, but this modem is not good quality from what I can tell so far.

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  • Levi D.
  • 2/22/2015 8:04:37 PM
  • Ownership: 1 month to 1 year

1 out of 5 eggsBuyer beware!

Pros: Easy to hook up and one phone call to the ISP had it online. Immediately ran a speed test and got 33.33M down and 3.5M up. Better speeds than the gear the ISP provided and no more rental fees, YAY!

Cons: I have an old Netgear router that is several years old and it still works great, figured this would too. I was wrong. It died quite suddenly after just 6 months (so much for saving me money on those rental fees). To all who purchase, keep your receipt on this one.

Other Thoughts: I gave a thought to contacting the manufacturer about this but I read quite a few reviews about Netgear and their service and warranty policies on this site and figured I'd just take the loss as it stands rather than let them rob me of more money and my time as well. I just tossed it and replaced it with another popular name brand and now I'm not BOARD, I'm SURFing. I'll never buy Netgear again.

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  • Keith L.
  • 2/7/2015 10:25:11 AM
  • Ownership: more than 1 year
  • Verified Owner

5 out of 5 eggsUpdated Review - One Year

Pros: Still working.

Cons: None

Other Thoughts: Seems to be a mixed bag from the reviews on here, but my experience has been good. It's paid for itself by now, having saved me the TWC modem rental fees over the past year.

I can't be sure what all the other reported problems are, but I do know that TWC only specs this modem for the low bandwidth side of their offerings, and I'm running at just their basic entry level.

It's glitched up maybe 3-4 times over the past year, but it's never required anything more that a power cycle or two to reset itself properly.

Overall, a solid purchase for my usage case.

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  • Bruce S.
  • 12/1/2014 12:32:31 PM
  • Ownership: more than 1 year

1 out of 5 eggsNo to Netgear MODEM

Pros: It is fast when it is connected to Comcast

Cons: I have to reboot this almost once a week to re-connect to the Internet, very painful when you have young kids trying to get on the Internet or streaming movies. I will be my last Netgear product. Going back to the brand I have used in the past.

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  • Darien C.
  • 7/20/2014 5:49:35 PM
  • Ownership: more than 1 year

1 out of 5 eggsProblems with Comcast Business Class

Pros: Worked for a while with residential at 100MB+

Cons: Does not work with business class and since residential is basically unusable for heavy internet users due to ridiculous data caps, if you use Comcast, avoid this modem. I am able to get 30MBs service tops. THe problems is supposedly in the "boot file" comcast attempts to load, but they've been working on it for 2 months and its still broken. Probably comcast's fault, but still, avoid the modem if you use comcast.

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1 out of 5 eggsDon't buy this product

Pros: no cd setup

Cons: This product is NOT compatible with Xfinity/Comcast....
Every night when not in use, this modem "disconnects" from my Xfinity internet service... I have to reboot it EVERY morning when I wake up... Comcast blames Netgear, and Netgear blames Comcast... 7/17/2014

Other Thoughts: Just buy a Motorola modem and save yourself the headache....

Manufacturer Response:

Hi Letigre,

Please email us at provide a copy and paste of your review and any case numbers you received from support.



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1 out of 5 eggsRIP Modem (2013 - 2014)

Pros: This is a follow-up review.

Previous review cited:
Easy set-up
Indicator lights

Cons: Previous review cited:
No appreciable improvement in speed.

So what happened? Well, the modem stopped working. The upstream connection was bad for months and my cable company actually believed it was their fault. They were going to come out, troubleshoot, install new coax, etc. After three months with no alternative but a big serious service visit from the cable co. to potentially rewire my whole building, they walked me through some more troubleshooting and (surprise!) it's the modem. Confirmed 100% it's the modem.

Call up Netgear, go through the whole spiel hear all about the service packages I can buy -- no, thanks, I just want my broken product fixed or replaced.

Sorry, they say, it's out of warranty. When I insist that the problems started before the warranty occurred, they tell me that this is irrelevant. When I stand by my assertion that the problems originated in the warranty period, they relent -- they know how the law views warranties, and that this must be covered. But they can't shut up about how kind they are to give me a "grace period" (even though really, they're just honoring the warranty consistent with existing case law on warranties).

Great! I'm ready to get that RMA as soon as we work through the troubleshooting and find that the modem is broken. Except I can't work through the problem myself. In order to replace the unit, I have to go through Netgear support to determine that it is a brick. And that's not free. In fact, they want to sell me a service plan that costs more than the modem.

After speaking with them for an hour, I am told that there is no defect, that the hardware is perfect (which we can diagnose, apparently, by pinging the modem -- that's the entirety of the test!) and that I need to upgrade the firmware. For a big fat fee, they will tell me how to upgrade the firmware.

When I tell the guy there are no firmware updates for this modem on Netgear's website, he tells me the current firmware revision and before I have a chance to say "that's what I've got and this darn thing is still defective" he hangs up. "I can't give away tech support for free" he says.

I call back and I'm presented with the same options: Sit on the phone with tech support. If they can manage to fix the problem, pay them a huge sum of money (to fix a problem with hardware they should be fixing under warranty!). If they can't fix it, I won't have to pay and I'll get my RMA. But I can't get the RMA without phone support troubleshooting the problem, which means I can't get my RMA without risking a non-RMA fix for the hardware failure, for which I am charged $100+.

Sorry Netgear, I called for tech support. If I wanted to gamble, I'd go to Las Vegas. This is not an appropriate tech-support practice -- as far as I'm concerned, it's a racket. Operating out of India, I'm not sure whether that type of racket is legal.

Other Thoughts: My previous review stated "if it doesn't catch on fire or stop working, it's good." While there was no need to call the fire dept., this unit just plain stopped working. All through its death throes, power cycling the unit would fix the issue. My cable company told me they would replace the wiring to fix the signal problem, they'd do whatever they needed to do to fix it. But in the end, this modem was slowly dying for several months. When it finally kicked the bucket, Netgear had me on the phone for two solid hours trying to get me to pay for phone support just to get my RMA. I have better things to do. I'm not going to give somebody money to tell me a brick is a brick. I know it's a brick. It's supposed to be a modem. That's why I want it fixed or replaced. I shouldn't have to litigate my way to a replacement, gambling on whether or not phone support can fix the problem.

This process is incredibly disappointing. This is a premium product in a market where most people get modems for free from their providers. Netgear needs to own up to the poor workmanship of this product -- which is evident from the reviews that have piled up since I wrote my previous review one year plus two weeks ago. They need to provide people with a path to RMA that does not require them to risk steep customer service charges if it turns out the issue was some non-RMA issue for which Netgear is still responsible. This is a class-action suit waiting to happen.

Netgear has a history, in general and with this unit in particular, of taking a very strict interpretation of what their warranty covers -- hardware only. They won't do ANYTHING for you unless you (1) have a problem with hardware, not firmware, software, or other problems that could be Netgear's fault and (2) you pay them for the phone support to determine that you do have a hardware problem.

This is a complete joke, and based on my two hour merry-go-round with people trying to sell me a service plan and refusing to issue me an RMA unless I bought one, customers are the but of the joke. If you buy a Netgear product, you should interpret ANY warranty statement as "90 day window for tech support, with RMA only if the physical hardware is defective." They had me ping my modem over a direct ethernet connection and RULED OUT ALL HARDWARE DEFECTS based on a ping! I nearly laughed out loud, except I had already been on the phone 70-80 minutes at that point and was not in the mood. Netgear probably turns a big profit on its support, and it sounds to me like they don't mind if a few of their units mysteriously break -- they make cash on both ends, so to speak.

The downgrade two one egg is really better than this product deserves, considering it will still average out to 2.5 eggs considering my previous 4-egg review.

Manufacturer Response:

Hi Anonymous,

We want to assure you that we stand behind our products and are here to help. We want to follow up with you on your support contact and do whatever we can to help. Please email us directly at and we'll look into this immediately.



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Item#: 9SIA0AJ35M9325
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