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NETGEAR Cable Modem CM400 - Compatible with all Cable Providers including Xfinity by Comcast, Spectrum, Cox | For Cable Plans Up to 100 Mbps | DOCSIS 3.0, Black, 8x4 Cable Modem (CM400)

4.3 4.3 out of 5 stars 7,303 ratings

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100Mbps Max Download
Single

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About this item

  • COMPATIBLE WITH ALL MAJOR CABLE INTERNET PROVIDERS: Including certification by Xfinity by Comcast, COX, and Spectrum. NOT compatible with Verizon, AT&T, CenturyLink, DSL providers, DirecTV, DISH and any bundled voice service.
  • SAVE MONTHLY RENTAL FEES: Model CM400 replaces your cable modem saving you up to $168/yr in equipment rental fees.
  • BUILT FOR SPEED: Best for cable provider plans up to 100 Mbps speed.
  • WORKS WITH ANY WiFi ROUTER: Connect any WiFi router to this modem's ethernet port to support all your wireless devices.
  • ETHERNET CONNECTIONS: 1 Gigabit Ethernet port connects to your computer or separate WiFi router.
  • MODEM TECHNOLOGY: Engineered with 8x4 channel bonding and DOCSIS 3.0.

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Legal Disclaimer

Sold as is. Not responsible for getting it working with your ISP. Make sure they support this modem.

Product Description

Product Description

The NETGEAR CM400 High Speed Cable Modem provides a connection to high-speed cable Internet, up to 340 Mbps. It is Cable Labs certified and with DOCSIS 3.0 is 8X faster than 2.0. It is compatible with U.S. cable Internet providers like Cablevision, Cox, Time Warner Cable, XFINITY & more.

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Technical Details

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Additional Information

Warranty & Support

Amazon.com Return Policy:You may return any new computer purchased from Amazon.com that is "dead on arrival," arrives in damaged condition, or is still in unopened boxes, for a full refund within 30 days of purchase. Amazon.com reserves the right to test "dead on arrival" returns and impose a customer fee equal to 15 percent of the product sales price if the customer misrepresents the condition of the product. Any returned computer that is damaged through customer misuse, is missing parts, or is in unsellable condition due to customer tampering will result in the customer being charged a higher restocking fee based on the condition of the product. Amazon.com will not accept returns of any desktop or notebook computer more than 30 days after you receive the shipment. New, used, and refurbished products purchased from Marketplace vendors are subject to the returns policy of the individual vendor.
For warranty information about this product, please click here [PDF ]

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NETGEAR

NETGEAR Cable Modem CM400 - Compatible with all Cable Providers including Xfinity by Comcast, Spectrum, Cox | For Cable Plans Up to 100 Mbps | DOCSIS 3.0, Black, 8x4 Cable Modem (CM400)


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From the manufacturer

cm400 high speed cable modem
Why Buy Your Own Modem?

Why Buy Your Own Modem?

Save up to 168 Dollars/year

Eliminates monthly rental fees that can amount to 168 dollars a year or more.

No WiFi limits

You’re free to choose & connect the best router for your home’s WiFi needs.

compatability

Compatibility

Swap modems. Not problems. CM400 is compatible with all major cable providers including Xfinity by Comcast, Spectrum, and COX.*

*Not compatible with Verizon, AT&T, CenturyLink, DSL providers, DirectTV, DISH and any bundled voice services

built for speed

Works with Any Wi-Fi Router

Easy 5 Minute Setup

Built for Speed

Supports cable internet plans with speeds up to 100Mbps ensuring fast, reliable internet speed for your home.

Works with Any Wi-Fi Router

Plug the modem into the router that best meets your wireless needs and start streaming.

Easy 5 Minute Setup

Step 1: Plug your coax cable into the modem.

Step 2: Activate by either

(a) connect an Ethernet cable to your computer and follow the on-screen setup, or

(b) call your cable provider to activate over the phone.

Step 3: Plug an ethernet cable between the modem and your Wi-Fi router.

cm400 cm500 cm500v cm600 cm700 cm1000
CM400 CM500 CM500V CM600 CM700 CM1000
Customer Reviews
4.3 out of 5 stars
7,303
4.3 out of 5 stars
14,488
4.3 out of 5 stars
7,303
4.3 out of 5 stars
7,303
4.4 out of 5 stars
6,506
4.5 out of 5 stars
8,398
Cable Provider Compatibility All Major Cable Providers and Xfinity by Comcast, Spectrum, COX All Major Cable Providers and Xfinity by Comcast, Spectrum, COX Xfinity by Comcast All Major Cable Providers and Xfinity by Comcast, Spectrum, COX All Major Cable Providers and Xfinity by Comcast, Spectrum, COX All Major Cable Providers and Xfinity by Comcast, Spectrum, COX
Best for Cable Internet Plan Speed Up to 100Mbps Up to 300Mbps Up to 300Mbps Up to 400Mbps Up to 500Mbps Up to 1Gbps
Works With Any Wi-Fi Router
Gigabit Ethernet Ports 1 x 1G 1 x 1G 1 x 1G 1 x 1G 1 x 1G 1 x 1G
Telephone Voice Ports (Xfinity by Comcast Only) 2 Phone Lines
Modem Technology DOCSIS 3.0 and 8x4 Channel Bonding DOCSIS 3.0 and 16x4 Channel Bonding DOCSIS 3.0 and 16x4 Channel Bonding DOCSIS 3.0 and 24x8 Channel Bonding DOCSIS 3.0 and 32x8 Channel Bonding DOCSIS 3.1, 32x8 Channel Bonding, OFDM 2x2

Customer reviews

4.3 out of 5 stars
4.3 out of 5
7,303 global ratings

Customers say

Customers like the performance, ease of setup, value, and signal strength of the modem. For example, they mention that it works brilliantly, the activation process was extremely easy, and the included instructions were very clear. That said, some complain about the connectivity.

AI-generated from the text of customer reviews

1,886 customers mention1,442 positive444 negative

Customers like the performance of the modem. For example, they mention that it works brilliantly, and telephony works smoothly. They also say that the internet still works fine, and there have been no latency issues or other hiccups. Overall, most are satisfied with the performance and functionality of the product.

"...The modem has been rock solid since with no issues on the phone or voice side...." Read more

"...to handle the needs of the tech enabled home, it is a stellar dual-processor performer at an incredible price.No. I don’t work at Netgear!" Read more

"...this to take at least an hour due to past experiences ,but no Very fast and simple and this is much better than the Aaris modems plus better looking..." Read more

"...However the more we gamed the more we noticed that the lag spikes were becoming more frequent/intense, sometimes resulting in a full Disconnection..." Read more

725 customers mention680 positive45 negative

Customers find the setup process of the CM600 cable modem to be easy. They mention that the included instructions are clear and easy to understand. Customers also appreciate the amazing ping times and smooth interactive comms and gaming while watching videos.

"...Setting up the Netgear CM600 cable modem is as easy to setup as plugging it in and turning it on...." Read more

"...to take at least an hour due to past experiences ,but no Very fast and simple and this is much better than the Aaris modems plus better looking an..." Read more

"...Bracing myself for difficulty with Comcast, I was pleased at how easy setup was without ever having to speak to Comcast's clueless CS...." Read more

"...The setup is simple. 1. Remove your current cable modem. 2. Put this one in it's place. 3...." Read more

434 customers mention386 positive48 negative

Customers like the value of the modem. They mention it's good for the price, saves them $10 a month, and is an inexpensive combo that kicks butt. Some say that the installation was super easy. Overall, most are satisfied with the value and performance of this product.

"...than this modem is adequate and fits into a nice price point...." Read more

"...tech enabled home, it is a stellar dual-processor performer at an incredible price.No. I don’t work at Netgear!" Read more

"...It's not a bad product, and still saves you money, and performs well, but the glitch can force you to need a new one to get faster speeds, even..." Read more

"...So, I purchased this puppy. Yeah, it has a cheap price tag, but this little baby packs a punch. I pay for the Extreme package via Time Warner...." Read more

402 customers mention389 positive13 negative

Customers are satisfied with the signal strength of the modem. They mention that it is much more reliable than the Comcast modem that they had been renting previously. The hardware is perfectly fine, and the mode is not susceptible to issues reported on devices. The signal seems very strong, and it appears to be stable.

"...It also is based off a broadcom chipset and is not susceptible to the issues people are reporting on devices that have been based off the faulty..." Read more

"...Given the specifications and the high-quality components it does its particularly job incredibly well...." Read more

"...I am writing this on day 1 and it has improved streaming through the whole apartment to all Smart devices ,TV's with internet well all internet..." Read more

"Good modem. Using Speedtest.net, its faster and has much lower latency than the Puma chipped Motorola 6121 I had been using...." Read more

99 customers mention88 positive11 negative

Customers like the size of the modem. They say it is small but powerful. Some customers also mention that it takes up less space.

"...Just like described. Haven't had any problems, and also, it's really small. Takes up almost no space...." Read more

"...features is also one of its simplest; that of course being its small footprint...." Read more

"...compared the monster boxes Xfinity is using today, but it is significantly smaller and easier to place out of the way, especially since it does not..." Read more

"This Modem is amazing. The small size is perfect for saving space wherever you place it. It is about 1/3rd of the size of my factory ISP modem...." Read more

107 customers mention35 positive72 negative

Customers are mixed about the quality of the modem. Some mention it's a great piece of equipment for their Internet needs, very easy to install, and an excellent choice. However, others say that the web interface is not well made, the constant drop outs render it useless, and the plastic pieces fall off.

"...cable from my wifi router into this cable modem, the clear plastic plug just kept falling out of its port on the modem!..." Read more

"...A bit rough around the edges. I changed the password and the modem locked up. Took me two restarts before I got it back...." Read more

"...This is on their list of supported modems and is the most basic type you can get...." Read more

"...Of course I did not expect him to call me back. I feel that the waranty is a scam...." Read more

407 customers mention96 positive311 negative

Customers are dissatisfied with the connectivity of the modem. They mention that it doesn't provide WiFi connectivity and has a sudden internet connection issue. Some say that the mode has latency and intermittent connectivity. They also say that it would fail every time the connection went out.

"...tech support from xfinity, it was found that the modem stopped communicating with the ISP, and the boot file was locked, and even a factory reset..." Read more

"...The Netgear's box was unsealed, and (2) the flap to open the box was torn...." Read more

"...directly to the modem, at which point he played a game and the ping spikes persisted...." Read more

"...Since purchasing this modem, I have had no random cable dropouts from my ISP. Remember, it has no built-in wireless or wired router...." Read more

80 customers mention21 positive59 negative

Customers are dissatisfied with the temperature of the modem. They mention that it runs a bit warm and overheats when knocked over.

"...It does get slightly warm at the top , It been plugged in about 45 minutes now so i dont see it being a problem ...." Read more

"...I have also noticed it runs pretty hot. Maybe it is overheating and dropping packets? I dont know, but it is not working...." Read more

"...a struggle to put in place, and the best part is that the modem doesn't get very warm either, so we're very confident the NetGear CM500V's going to..." Read more

"...Not impressive. Runs hot to very hot. I point a little USB fan at it when I'm running high mbps rates (>5) for hours. Cools it right down...." Read more

No more cable modem rental fees for me!!
5 Stars
No more cable modem rental fees for me!!
It was time to start trimming my Time Warner Cable bill. So, I purchased this puppy. Yeah, it has a cheap price tag, but this little baby packs a punch. I pay for the Extreme package via Time Warner. I was averaging 80 megs down. After installing this and getting it activated, my download speeds are averaging over 115 megs down - that's both wirelessly and hard-wired. The setup is simple. 1. Remove your current cable modem. 2. Put this one in it's place. 3. Hard-wire it to a laptop or a desktop (yellow cable to the yellow port on back of cable modem, the other end to the internet port on your laptop or desktop. 4. Power on the modem (making sure you have already connected the coaxial cable as well. (When the globe stays a solid green with no blinking, it is recognized as being connected. 5. Turn to the activation page in the mini manual that comes with it. It will show various internet providers and their perspective links. 6. Open up a browser (with pop-up blocker offf) and follow the prompts. Odds are in favor you will get "due to your account settings, this will not work - call the 1-800 number shown." That's okay, call it. Tell the operator you are installing your own cable modem. The operator will ask for the MAC address (found both on the box and bottom of cable modem). Agent on the phone will first remove your current cable modem from your plan (or else, this will never work). You will power it off upon request, and back on again 30 seconds later. Go to a website of choice - and wa-la, you are back online!! No more cable modem rental fees!! BTW, I work in the IT field, and have for 25 years. This will be all the modem you ever need unless you plan to go over 450 megs in the future. I have the following items that may be online at any time and all at once: Xbox One, PS3, Two laptops, One desktop, one cell phone, and one tablet. I can play Netflix on all devices (4 at once since that's my Netflix account package), and there is no buffering at all. I bundled this with the Netgear WNDR4500 Dual Ban Gigabit Wifi Router. Here's my layout. Cable Modem feeds the router. The router feeds my 16-port switch. I work on computers on the side, so the switch comes in handy. Any questions? Feel free to ask me. Trim your cable bill and get this or any cable modem for that matter. Note, this is a cable modem only that does not supply wifi. It only has the internet-out port. There are no other ethernet ports on it. So, upgrade your router or get one. The model I mentioned above is a great match. You are welcome!!
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Reviewed in the United States on November 15, 2017
Style: 300Mbps Max Download w/VoicePattern Name: SingleVerified Purchase
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Reviewed in the United States on July 15, 2018
Style: 960 Mbps Max DownloadPattern Name: SingleVerified Purchase
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Ccpd
1.0 out of 5 stars Buena calidad, pero no me funciono.
Reviewed in Mexico on June 2, 2020
Style: 100Mbps Max DownloadPattern Name: SingleVerified Purchase
One person found this helpful
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