Skip to: | - A great place to buy computers, computer parts, electronics, software, accessories, and DVDs online. With great prices, fast shipping, and top-rated customer service - once you know, you Newegg.

If you are reading this message, Please click this link to reload this page.(Do not use your browser's "Refresh" button). Please email us if you're running the latest version of your browser and you still see this message. - Computer Parts, Laptops, Electronics, HDTVs, Digital Cameras and More!

  • Wish List
  • Feedback
  • Help
Search all
Home > 
Computer Hardware > 
Networking > 
Modems / Gateways > 
Motorola > 
Item#: N82E16825122015

ARRIS / Motorola SurfBoard SB6121 DOCSIS 3.0 Cable Modem

  • Compatible with Time Warner, Comcast, Charter, Cablevision, and others
  • Gigabit Ethernet connectivity
  • DOCSIS 3.0-certified (EuroDOCSIS 3.0-based)
  • Pin It
  • Email this page
ICON Loading...


SB6121 SURFboard Cable Modem RJ-45

Building upon the success of the SB6120, Motorola's SURFboard SB6121 delivers your complete personal media experience, at lightning-fast broadband speed. It harnesses the power of DOCSIS 3.0 technology to bond up to four downstream channels and four upstream channels - providing you advanced multimedia services with data rates of more than 100Mbps in each direction. That makes gaming, shopping, downloading, working, high-quality voice and video conferencing, and peer-to-peer networking applications far more efficient than ever before.



SB6121 Easy to Set Up and Use
  • Plug-and-play installation
  • Front panel LEDs indicate status and simplify troubleshooting
  • Multi-language user guides
  • Supports standard internet software
  • User-friendly online diagnostics

  • Stylish and space-saving enclosure
  • Offers innovative, high-bandwidth data and multimedia services to customers
  • Backward-compatible to DOCSIS / EuroDOCSIS 1.x and 2.0

Advanced Services Ready
  • DOCSIS 3.0-certified (EuroDOCSIS 3.0-based)
  • Channel bonding of up to four downstream and four upstream channels
  • 1GHz capable tuners
  • Supports IPv4 and IPv6 to expand network addressing capabilities
Versatile and Convenient
  • Compatible with Windows, Macintosh, and UNIX computers.
  • Gigabit Ethernet (RJ-45) data port enable flexible, high-speed connectivity with Auto Negotiate and Auto MDIX

Reliable and Secure
  • Enhanced security: supports Advanced Encryption Services (AES) traffic encryption
  • Remotely configurable and monitorable using SNMP and TFTP

As part of Motorola's DOCSIS 3.0 Ultra-Broadband family of products, the SB6121 includes an enhanced tuner that supports up to a 1GHz downstream input, which allows operators to increase the frequency spectrum for deployment of new high-value service - such as bandwidth on-demand, commercial services, interactive gaming, and IPTV. The SB6121 features a 10/100/1000 Base-T Ethernet (RJ-45) port, as well as intuitive, easy-to-read front-panel operational status LEDs.

What Is DOCSIS 3.0?

With the DOCSIS 3.0 specification, cable Internet providers can take advantage of the extra capacity provided by channel-bonding technology in order to offer ultra-fast broadband services. Channel bonding allows parallel data pipes to act as a single broadband conduit. With each channel capable of providing around 40Mbps of data, the Motorola SURFboard SB6121's four downstream channels can provide a theoretical maximum of 160Mbps of throughput.

Currently, cable providers max out at around 50Mbps of downstream data throughput, but DOCSIS 3.0 will enable cable Internet providers to continue to improve the speed of their networks.

System Requirements
The SB6121 is compatible with the following operating systems:
  • Windows 7
  • Windows Vista, Service Pack 1 or later
  • Windows XP, Service Pack 2 or later
  • Mac 10.4 or later (Ethernet connection only)
  • UNIX (Ethernet connection only)
  • Linux (Ethernet connection only)

What's in the Box

Motorola SURFboard SB6121, Ethernet cable, Installation sheet


Learn more about the Motorola SB6121




Cable Modem
1 x RJ-45, Gigabit Ethernet
Cable Interface
75ohm F-connector
DOCSIS 3.0, 2.0 and 1.1, Euro-DOCSIS 3.0
Max Transmission Rate
Up To 172 Mbps Down and 131 Mbps Up


Data Protocol: TCP/IP

Power: 9W (nominal)

Input Power: 105 to 125 VAC, 60 Hz

-Modulation: 64 or 256 QAM

-Capture Bandwidth: 100 MHz (edge to edge)

-Maximum Theoretical Data Rate:
DOCSIS: 171.537 Mbps (4 channels) / 42.884 (single channel)@ 256 QAM at 5.36 Msym/s
EuroDOCSIS: 222.464 Mbps (4 channels) / 55.616 (single channel)@ 256 QAM at 6.952 Msym/s.

DOCSIS: = 24 MHz
EuroDOCSIS: = 32 MHz.

-Symbol Rate:
DOCSIS: 64 QAM 5.057 Msym/s; 256 QAM 5.361 Msym/s

EuroDOCSIS: 64 QAM 6.952 Msym/s; 256 QAM 6.952 Msym/s.

-Operating Level Range: –15 to 15 dBmV

-Security: DOCSIS 3.0 Security (BPI+, EAE, SSD)

-Network Management: SNMP v2 & v3

-Provisioning Supports: IP addressing using IPv4 and/or IPv6 (dual stack).

-Modulation: QPSK and 8, 16, 32, 64, 128 QAM

-Maximum Channel Rate
DOCSIS 131.072 Mbps (4 channels) / 32.768 Mbps (single channel): @ 128 QAM at 6.4 MHz
EuroDOCSIS 131.072 Mbps (4 channels) / 32.768 Mbps (single channel): @ 128 QAM at 6.4 MHz.

-Channel Width 200 kHz, 400 kHz, 800 kHz, 1.6 MHz, 3.2 MHz, 6.4 MHz

-Symbol Rates: 160, 320, 640, 1280, 2560, 5120 ksym/s

-Frequency Range: DOCSIS 5-42 MHz (edge to edge), EuroDOCSIS and optional DOCSIS 5 to 65 MHz (edge to edge)

Compatibility PC: 90496, Pentium, or later; Windows Vista, 2000, XP or 7 or Linux with Ethernet connection (older versions of Windows, although not specifically supported, will work with this cable modem).
Macintosh: Power PC or later; OS 9 or higher, Ethernet connection.
UNIX: Ethernet connection.
Home Networking: Ethernet router or wireless access point.


Package Contents
Ethernet Cable
Power Supply
Software License & Regulatory Card
Product Guide (Install Sheet)

Manufacturer Warranty

1 Year Limited Warranty
1 Year Limited Warranty

Quick Info


  • Limited Warranty period (parts): 1 year
  • Limited Warranty period (labor): 1 year

Customer Reviews of the Motorola SB6121

Do you own this product? Write a Review

ICON Loading...

Filter Results

  • Joseph G.
  • 5/21/2015 2:43:47 PM
  • Tech Level: Average
  • Ownership: 1 day to 1 week
  • Verified Owner

3 out of 5 eggsGood, with a possible caveat

Pros: Easy to install, fast and knowledgeable customer service.

Cons: Possible bad firmware, leading to problems with connection speeds.

I activated the modem with my service provider (Cox), but was only seeing ~30Mbps down with a 50/5 connection service. After several service calls and a tech visit, my provider determined the gateway was the problem. I contacted ARRIS support and we found that I was only getting a single channel connection, where I should have been getting four.

I then had to re-contact my service provider to have them re-provision the modem. The level two tech that assisted me said that this was actually an issue with the ARRIS firmware, and it was only allowing them to lock a single channel. She updated the modem using their Cox firmware and was able to resolve the issue.

TL;DR: Getting the connection at the right speed may take additional time and effort.

Other Thoughts: Regardless of whether this was a Cox issue or a gateway issue, I'm giving this three eggs. It's a good product, but getting it working correctly may not be as easy as advertised.

Did you find this review helpful? Yes No

  • Scott J.
  • 5/15/2015 7:56:15 AM
  • Tech Level: High
  • Ownership: 1 week to 1 month
  • Verified Owner

5 out of 5 eggsMotorola SB6121 Cable Modem

Pros: It totally works, Dude! A quick call to my service provider and they set up the service and I returned their stupid $6.00 a month modem to them.

Cons: None so far.

Other Thoughts: I thought about the newer model but as part of a package with the router too, wow, what a good deal. Newegg you rock.

Did you find this review helpful? Yes No

  • Joshua W.
  • 5/15/2015 7:52:39 AM
  • Tech Level: Somewhat High
  • Ownership: 1 month to 1 year
  • Verified Owner

5 out of 5 eggsSaves money, works great

Pros: -No issues at all
-Saves me money on my internet bill
This product is simple to set up. Just hook it up, call the ISP (Time Warner in my case) and it is done. Not having to pay the equipment fee every month is nice, and this is more than fast enough for any plan available in my area.

Cons: None come to mind. It works great and saves me money. What else could I ask for?

Other Thoughts: After getting this on sale (with a free item included as well) and it saving me $9 a month, it should pay for itself within 8 months.

Did you find this review helpful? Yes No

  • Conan W.
  • 5/6/2015 7:58:00 PM
  • Tech Level: Average
  • Ownership: 1 month to 1 year
  • Verified Owner

5 out of 5 eggsWorks great - get ride of the modem rental fee

Pros: Works to get rid of the modem rental fee! Makes no noise and is attractive looking. Wall mountable.

Cons: none

Other Thoughts: If you want or need 100mbps or higher internet you need to buy the newer version. I don't see a need for that fast of speed since I use WIFI most of the time and you can't get that fast of speed over wireless without A/C equipment which I don't have.

Did you find this review helpful? Yes No

  • Igor B.
  • 5/1/2015 7:59:59 AM
  • Tech Level: High
  • Ownership: 1 day to 1 week
  • Verified Owner

5 out of 5 eggsTWC Modem

Pros: TWC 50/5 service. No issues whatsoever. Getting advertised speeds.

Cons: none so far

Other Thoughts: Through the router, servicing 3 devices at a time with no issues.

Did you find this review helpful? Yes No

  • Chad P.
  • 4/28/2015 6:57:57 PM
  • Tech Level: High
  • Ownership: 1 month to 1 year
  • Verified Owner

5 out of 5 eggsGreat modem for a awesome price!

Pros: - Great speeds

- No longer have to pay ISP for "rental" fees for their aging hardware

- Nice design

Cons: None

Other Thoughts: This modem was a great replacement for the "rental" modem I was paying for from TWC. This guy will pay for himself in no time (since prices are going up on hardware with my ISP). Great shipping time from Newegg as always.

Did you find this review helpful? Yes No

  • Charles S.
  • 4/2/2015 11:40:26 AM
  • Tech Level: Somewhat High
  • Ownership: 1 month to 1 year
  • Verified Owner

5 out of 5 eggs

Pros: Easy peasy lemon squeezy. Switched to Comcast and wanted to save some money each month. Looking at this as an investment - in 7 months I'll have this router paid for and after that I'm saving $$$. Make sure you have a router that won't bottleneck your internet speed because your modem won't be the bottleneck any more!

Cons: No cons on my end. Couldn't have been easier to set up.

1 out of 1 people found this review helpful. Did you? Yes No

  • Lyle S.
  • 3/30/2015 3:06:51 AM
  • Tech Level: Average
  • Ownership: 1 day to 1 week
  • Verified Owner

5 out of 5 eggsWhy rent a shoddy modem?

Pros: I decided to upgrade my internet speeds to the top tier Comcast offers me but I was infoirmed that my current modem I was renting from them wasn't powerful enough and also told the only way to get the speeds I need was to buy my own. This is fine by me as it's less money I have to give to Comcast. Modem took less than 10 mins to get up and running. Any and all problems came on Comcast's end.

Cons: Comcast. (Obviously not the fault of Motorola)

Other Thoughts: Worth the money to ease Comcast's grip on me.

1 out of 1 people found this review helpful. Did you? Yes No

  • Jonathan G.
  • 3/29/2015 12:50:14 PM
  • Tech Level: Somewhat High
  • Ownership: 1 month to 1 year
  • Verified Owner

5 out of 5 eggsMotorola SB 6121

Pros: Easy set up. Faster speeds.

Cons: It took a few days to see my speeds ramp up to the max speeds of my ISP but this could be related to changing from the DOCSIS 2.0 to 3.0.

Other Thoughts: I love Motorola modems. I have my motorola surfboard 5100 for about 8 years and it has been rock solid.

Did you find this review helpful? Yes No

  • Stephen S.
  • 3/19/2015 6:36:55 PM
  • Tech Level: Somewhat High
  • Ownership: 1 month to 1 year
  • Verified Owner

5 out of 5 eggsEggcellent

Pros: -Run Cool
-Very bright LED's make a good night light in the server room
-Reliable at least more than the cable company itself
-low latency from end to end
-exceeds the speeds I paid for (also dependent on cable company)

Cons: It doesn't make me breakfast, other than that none really =)

1 out of 1 people found this review helpful. Did you? Yes No

Compare Offers from All Sellers

Seller Name & Rating Offer Details  
ICON Loading...

Send It As A Gift!

gift services details

More Buying Options

Are you an E-Blast Insider? Subscribe Newegg e-Blast
Shop without retyping payment details. Secure shopping made faster.
Check out with PayPal.

Home > 
Computer Hardware > 
Networking > 
Modems / Gateways > 
Motorola > 
Item#: N82E16825122015
Related Products
42Mbps Downstream,10.2Mbps Upstream USB and Ethernet 10/100Base T ...
The MultiModem® ZBA business modem supports remote configuration ...
The GT784WN Wireless N DSL Modem Router is ...
Shop by Region: United States | Canada | China | Taiwan
VeriSign Click for the BBB Business Review of this Computers - Supplies & Parts in Whittier CAThis site protected by Trustwave's Trusted Commerce program Inc500
Policy & Agreement | Privacy Policy  © 2000-2015 Newegg Inc.  All rights reserved.
If the Adobe Reader does not appear when you click on a link for a PDF file, you can download Adobe Reader from the Adobe web site.