Best Cable Modem

Cox has upped their connection speeds again and says that this type of modem is required (I currently have a DOCSIS 2, Motorola SB5120)...

DOCSIS 3 modem with 8x4 channel support

Recommendations for best brand/model?

Thanks! ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Reply to
Jim Thompson
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Are you sure you can just hang a modem on that Cox cable, instead of getting one from them? Usually they use the MAC address for tracking who is on their system, and use the remote management features in the modem for trouble shooting.

Cheers

Reply to
Martin Riddle

Cox approved/recommended/tolerated modem list:

I use Motorola/Arris SB6141 on Comcast. It does 8x4 bonding for over

300 Mbits/sec. Costco has them for about $80.

The SB6182 is an SB6180 in a smaller box with 8x4 bonding and made exclusively for Cox. Good luck finding a SB6182 data sheet but the SB6180 is allegedly close: The SB6183 is faster with with 16x4 bonding for over 600 Mbits/sec. I haven't had a chance to play with these two yet.

I strongly suggest you stay away from the conglomerated gateway boxes with a modem, router, wireless, and ethernet switch in one package. They drive me nuts.

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

Here, in AZ, you can rent one from Cox, or buy your own...

...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Reply to
Jim Thompson

Agreed! I maintain a simple-minded WiFi add-on for the grandkids... disabled except when they visit.

I was tending toward the SB6183. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Reply to
Jim Thompson

Yes, but that's not why I suggested you stay away from the gateways. The problem with conglomerated gateway boxes is that invariably, there's some part that needs to be upgraded or was released with buggy firmware. Instead of tossing the box that needs an upgrade, you end up tossing the entire gateway and starting over. Even worse, the cable vendors charge about 8% of the purchase price to rent a gateway. If you're going to keep the box for more than about a year, you might as well buy it.

Some of these boxes are made exclusively for the cable vendor, and cannot be legally purchased. If you find one on eBay, the cable service provider will often refuse to activate it claiming that it was "off lease" and therefore the property of the vendor. Or, it it has some other providers firmware, they may claim that it can't be reloaded with their own firmware. I got tired of buying perfectly good modems on eBay that can't be activated and switched to a vendor that guarantees that it will be acceptable: $62 for the SB6141, which is less than I pay at Costco. Hmmm....

Bad idea. All of the 8x4 modems will do DOCSIS 3.0 which is fine for todays technology. However, the first deployments of DOCSIS 3.1 will arrive sometime in 2016. If you're buying the SB6183 in order to future proof your modem purchase, you'll get maybe 2 years of use before you might need to upgrade again. It's possible that the SB6183 can be upgraded to DOCSIS 3.1 in firmware, but there's no promise or guarantee at this time. I suggest you stay with DOCSIS 3.0 8x4 modems for now and not treat the modem as some manner of investment.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

The reviews on Amazon for the SB6141 say the _black_ SB6141 has/had a firmware bug, but these reviews are a year or so old. Do you know anything about that? ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Reply to
Jim Thompson

No, and it probably doesn't matter. Your cable ISP will upload to the modem its very own custom firmware when you activate the device. That's the main reason for the approved modem list.

Be sure to *NOT* power off the modem until you're certain that it has updated the firmware, which usually culminates in a reboot. Takes about 15 mins. When in doubt, leave it alone for about an hour after activation. If you pull the plug before it's done, you could end up with a "bricked" modem. I've only seen it happen once which was once too often.

I haven't seen any of the black SB6141 routers. All the SB6141 modems I've purchased, resold, recommended, or obtained via eBay were white. The only problems I've seen with the SB6141 are variations in input sensitivity. After the last big storm, there was water in the cable system, causing reduced signal levels. Normal is 0dBm minus what the splitters burn (-3.5dB each). During and about a week after the storm, the levels at many modems dropped to about -10dBm. Some modems just stopped operating complaining of insufficient signal with a truly cryptic flashing diagnostic light show. Most modems usually work down to -15dBm so this was rather unusual. To placate one irate customer, I swapped his somewhat insensitive SB6141 modem with an identical but more sensitive replacement modem that worked down to -15dBm. That kept them online until the cable dried out. Since it never rains in Phoenix, I don't expect you to experience this problem.

Incidentally, you can see your signal levels by pointing your web browser to: I don't know if Cox uses the same IP address, but it works for Comcast. You can test your modem for proper signal level BEFORE you activate it. In some areas, you can surf to the ISP's activation and test sites.

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

Ha! When it rains here, so much flows it would stop the East coast in its tracks. Once upon a time when I had a landline phone, every time it would tinkle, the phone would develop a buzz :-(

Worked. I'm showing +4dBmv downstream, 37dB SNR ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Reply to
Jim Thompson

You're doing fine. You'll need one more number, the upstream signal level.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

Just one note: if you have a UPS powering the modem, it will matter what the power draw (and VA as well as watts) is. Lower is better, of course.

Reply to
whit3rd

Enormous... +41dBmv ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Reply to
Jim Thompson

Not so enormous. CATV levels are usually measured in reference to 1 millivolt across 75 ohms: +41dBmV(75ohms) = -7.75 dBm(75ohms)

The +41dBmV upstream signal is the minimum signal level that your modem needs to make the CMTS (cable modem termination something) happy. Smaller numbers mean less upstream cable loss. Larger numbers mean that there are upstream losses somewhere in the cable system. Enormous is bad.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

Thanks for the info.

Dan

Reply to
dcaster

Yes, catv signals are measured in dBmV, not dBm.

+41dBmV for the output of the upstream signal is About right.

Mark

Reply to
makolber

The difference is in what the signal is compared or referenced to.

at 75 Ohms for CATV.

Check these figures and conversions...

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Reply to
DecadentLinuxUserNumeroUno

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