NETGEAR Cable Modem CM400 Compatible with Cable Providers Xfinity by Comcast, Spectrum, Cox | For Cable Plans Up to 100 Mbps | DOCSIS3.0, Black (CM400-100NAS)

Time Warner charges a monthly fee for provided modems but allows customers to purchase their own modem as long as it's on their approved modem list. I purchased this Netgear Modem to lower the cost of my monthly Time Warner internet charges. It will take about 13 months for it to pay for itself. I'm sure it will last much longer than that since I have always had luck with Netgear products. It was very easy to install. I just took the cables off Time Warner's modem and attached them to the new modem. The initial boot-up of the modem took about 5 minutes to complete but the manual said it could take up to 15 minutes. After the initial boot-up I had to call Time Warner to activate it. That process took me about 10 minutes on the phone with a Time Warner tech. The manual lists all the supported cable ISP's along with websites and 800 numbers so you can easily contact your ISP for activation. The manual also includes suggested dialog to use when talking with the tech to make things easier. Comcast customers can activate their modems via Comcast's website. I did a speed test after the activation and everything was as expected.Pros:Nice Design, Matches the rest of my Netgear equipment.Easy to setup.Clear instruction manual.Lowered my monthly internet bill.Can login to the router for configuration, logs, and statuses (Could not with my TW Modem).Cons:None so far.

We liked how easy it was to setup.

First one out of the box set up easy but within 24 hours started constant cycling to find connection. Took over a half an hour to get to a Netgear tech and 2 to 3 hours of trying everything he could think of, including re-flashing the firmware, with the end result being getting issued an RMA for a replacement unit. Took 5 days to get the replacement although I asked for expedited shipping. Set up for the replacement unit was easy and it's been running just fine for a couple of weeks with no problems. So far so good. It's hooked up to a Netgear N600 wireless router and the two seem to talk to each other with no problems.

The CM400 is primarily a simple device to install. Due to the restrictions placed on us by the cable provider, i.e. firmware updates, a particular downstream channel frequency and the like, there is however only one controlling feature for us to modify. Compared to the many other units I've used this cable modem does allow us to at least find a starting frequency then locking into a channel best suited to my custom router/networking needs. It does take a few extra tries to find that one frequency I'm looking for, that's the one controlling feature I like that Netgear gives us. My regional cable provider is not always in alignment to my speed freakish needs limited to 110Mbps. :<(' The CM400 is a very reliable and sound unit. Bought April 2017, over a year of quality service.

Right out of the box this product would reboot itself every 1-2 minutes. Obviously your not going to have luck doing anything on the web when you are constantly dropping your connection for a reboot. After doing some research on this issue I quickly discovered that a firmware update should resolve the issue. I verified the current version and compared it to mine and sure enough I was about 6 versions out of date. This is good - it means I have a simple fix ahead of me... or so I thought because updating the firmware should be about the simplest thing you can do on any piece of hardware.I expected to find a link in the GUI (this is the interface where you access the controls/settings for the device through an internet browser) which would say something like "Check for updates". But, no such link exists. So, I thought perhaps I could simply download the required files from the support page much like you might for driver.... Nope!After doing a little digging on NETGEAR's site I found that in order to update the firmware I had to reach out to the ISP (Internet Service Provider), who in my case is Spectrum (formerly Time Warner Cable). They were very quick to tell me that they can't update the firmware because it's not their device - I purchased it myself, I'm not leasing it from them. So, I reached out to NETGEAR who told me that they can't help me. They reiterated what I previously read on their site that it must be done by the ISP. I tried the Spectrum again hoping the last person that I spoke with there maybe just didn't know what they were doing... and I was told the same thing again. So I called NETGEAR back to find out what can be done. They insisted that they cannot support their own equipment and I needed to get support from the ISP. I started getting seriously frustrated at this point. I asked the rep at NETGEAR "how could you make a product and then not only take away the users ability to maintain their own equipment especially when it comes to firmware updates which are often critical to network security, but you the manufacturer wont support it? How can you rely solely on third-party ISP's all over the globe to maintain your equipment for you?" Instead of responding, he hung up on me. Just like that. I never swore and I never raised my voice. I guess he just didn't have an answer and didn't value me as a customer.Long story short - I'll never buy another NETGEAR product again! And I don't recommend you do either!

No complaints about functionality. When I purchased this modem less than 1 year ago, the description said it would work with Oceanic Time Warner (OTM) I was told that it was rated at 340MBPS. At the time I was considering upgrading to faster upload speeds. I am now upgrading to 200 MBPS service. OTM and they tell me this modem is too slow and that I need a modem rated at 300 MBPS, such as the C3000, C3700 or C7000. I am not a computer genius, but this seems to be a conflict of specifications. I feel that either Amazon or Netgear should give me credit for this purchase toward an upgrade, or educate OTW if it is their misunderstanding. I am willing to upgrade, but feel that I have been misinformed by someone. I realize that technology is advancing, but a purchase 11 months ago should still be usable at the specified speed.