SMC Networks D3CM1604 Modem (DOCSIS 3.0, 16x4 Channel Bonding) Approved for Time Warner Cable, Charter, Cox, Spectrum

I bought this to replace a Motorola SB6121 for service on Comcast after I got an email from Comcast saying that I could benefit from a new modem. I have Comcast Blast! internet service and am in the 21093 area code.ACTIVATIONI followed the Comcast activation instructions here:https://customer.xfinity.com/help-and-support/internet/activate-purchased-modem/I connected my Macbook Pro directly to the ethernet on the modem and used the Safari browser during activation. Everything went smoothly. The only problem I had was that after activation many web pages (not even comcast) redirected to the Comcast Activation page. This happened only in Safari, not FireFox or Chrome. I was a bit puzzled but solved it by clearing the browser history for the day. Since activation the power light is green, the DS light is solid blue, the US light is flashing amber (probably because I only have 3 upstream channels, see below), and the Link light is solid blue.SPEEDI have tested speeds using speedtest.net and speedof.me several times over the last day. I did this with the modem connected through my Asus RT-N66R router runing asuswrt-merlin. My macbook was connected via GB ethernet through a switch to the router. I have gotten download speeds of 180-200 mpbs consistently. Upload speeds have been 10-13 mpbs. On my iPhone 5s connected by wifi I have gotten 70-80 mpbs download and 12-13 mbps upload when located 5 feet from the router using the Ookla Speedtest app and the speedof.me Lite test on the speedof.me website.MODEMContrary to some reports, the temperature of my modem is very reasonable. It felt a little warm to the touch near the top, but room temperature elsewhere. Just for grins I measured the temperature using an infrared heat gun and found it to be between 65-90 F (18-33 C), with the hotest being at the top of the modem. Room temperature is about 62 right now. So, no problem with heat for me.The modem came with no manual (only a small 'lawsuit avoidance' booklet). I found the manual here, but it wasn't particularly helpful.http://na.smc.com/wp-content/uploads/2014/12/D3CM1604_Cable_Modem_Manual.pdfThe modem has some status pages, but you have to know how to access them. I found some information in various forums. Here is what I learned.The forums say that you must use Safari or Chrome. I used Safari.You can find basic status at 192.168.100.1. This shows basic connection status, serial number, etc.There is a place to login. The username and password on mine were admin and password, respectively.After logging in I was able to go to the security page:http://192.168.100.1/RgSecurity.aspThis has options to let you turn on a spectrum analyzer, turn on telnet access, and reset to factory defaults. I did not try the latter. On mine, telnet access was on but the spectrum analyzer was off. I turned on the spectrum analyzer and hit apply. I couldn't figure out how to go to the spectrum analyzer until I found this discussion:http://dslreports81.rssing.com/browser.php?indx=13595052&item=3689In summary, the spectrum analyzer is accessed at192.168.100.1:8080I must confess that I didn't play around with this a lot to see if it is useful, etc.You can also access an event log at:http://192.168.100.1/RgEventLog.aspMine has been running for about a day and there aren't very many items in it. Only a few that seem to be related to the original provisioning. Unfortunately, there are no time stamps in the log so I can't tell for sure.I tried telneting to 192.168.100.1 and was connected to a telnet daemon. However, I couldn't figure how to login. The admin/password that worked on the web page didn't work here.It is a bit irritating that the modem doesn't allow me to change the password and makes accessing some of the features a bit of a magic incatation. For example, after logging in if you click on one of the buttons on the left of the UI, e.g., connection, the other buttons vanish on the new page. There is not, that I could see, a link to the event log page and I only found it by guessing. I only found the spectrum analyzer by googling. Who knows what other goodness lies hidden from view. I suspect this has more to do with Comcast than SMC.My current connection, as indicated on the connection page, has all 16 downstream channels linked. The SNRs vary from 37.7-42.9 dB. The powers range from -2.3 dBmV to -.3 dbBmV. I have only 3 upstream channels that are connected. They all report 5120 Ksym/sec and powers of 41.3-43.3 dBmV.SUMMARYSo far (after 1 day) the modem has lived up to my expectations. I got a 30-50 mbps increase in downstream speed, but nothing in upload. I'm not sure it was worth it for the extra speed, but have read that this may make me more immune to local congestion. I haven't tested it during times when congestion is high. I am a little disappointed that some of the advanced features of the modem interface are hidden, but since I was able to find them and since I am not sure how useful they will be compared to the simple connection speed I did not downgrade the rating. I will update this review later if things change.

SMC Networks D3CM1604.Love it! This unit works well. It is functions with "Comcast" located in Miami Dade County. The speed is excellent. Lights are attractive and a perfect match to the Asus Dual Band 3x3 802.11AC Gigabit Router. Sleek design. Simple to install. Saving over $10 a month by not renting a modem. I love the unit and would recommend to others.The Motorola ARRIS SURFboard SB6183 is comparable; however, it is $35 more and WHITE: Two thumbs down.The SMC Networks D3CM1604 is fantastic! Buy it.Notes:(1) Make sure to clear your Routers WAN and set to Auto IP.(2) The US or DS will blink "green" if your provider (such as Comcast) is not utilizing all of the 16 channels down or 4 channels up. In my case Comcast list 4 channels US. However they utilize 3 channels and keep one channel zeroed for future options. The modem indicates this observation by flashing green on US. To see your channels provided by your provider go to your modem login.The SMC Networks D3CM1604 is fantastic! Buy it.

Using this modem with Mediacom and it is working just fine. Mediacom uses D3CM1604V (voice capable version) so I figured this modem should work just fine. In my opinion it is better than Arris/Motorola SB6183 (cheaper and it's also a 16x4 modem). Keep in mind you should probably expect no firmware updates at all. I would not be surprised if SB6183 receives firmware updates in the future. Also note unless your company is providing 16 downstream and 4 upstream channels your DS and US LEDs will never go solid blue but will blink green all the time (unlike the D3CM1604V version which will go solid blue if it is bonding to all available channels from your cable co and I believe this change was added in a later firmware update). For those of you familiar with cable modems this may look like the modem is trying to do a firmware update but that is not the case. Blinking green simply indicates the modem is not bonding to all 16x4 channels which is not an issue but may be annoying if you have your modem in your bedroom (to be honest bright blue LEDs are not much better but at least they are not blinking). Using it with Mediacom's 150 Mbit down and 20 Mbit up serviceMy modem arrived with firmware D3CM1604-B559.2.8-RES_GA.