Home / Collections / Comcast Replacement Devices / Motorola Multi-Gig Speed DOCSIS 3.1 Cable Modem | mb8611 - Comcast Replacement

Motorola Multi-Gig Speed DOCSIS 3.1 Cable Modem | mb8611 - Comcast Replacement

Motorola Multi-Gig Speed DOCSIS 3.1 Cable Modem | mb8611 - Comcast Replacement

$143.99 $189.99 saving $46.00
| /
$143.99 $189.99 saving $46.00
| /
  • Description
  • Tech Specs
  • Limit 2 per customer

    ultra-fast DOCSIS 3.1 performance

    Stream, game, conference and more with confidence. DOCSIS 3.1 supports speeds up to 10x faster with higher efficiency. Also backwards compatible with 32x8 DOCSIS 3.0 so you can future proof your network.

    true multi-gigabit speed

    Don’t let your cable modem throttle your speed. A 2.5 Gbps Ethernet port delivers high-speed connectivity to even the fastest routers and computers.

    works with any router

    Seamlessly pair with any WiFi router to connect all your wireless devices. This cable modem does not have a built-in wireless router or telephone capability.

    superior and pays for itself

    Savings up to $168 per year on modem rental fees with your internet provider. Certified for Comcast Xfinity, Cox, and Spectrum and compatible with IPv6.

    simple setup and use

    Easy self-installation. Comes with a 2-year warranty and free support from our team of US-based technicians.

    motosync app

    It's like having our product experts in your home with one tap using in-app live chat support.

    *Coupon codes not valid with Comcast Replacement Product Listings

  • General

    Cable Modem Service Interface

    • F-type female 75 Ω (standard coaxial connector)

    Ethernet Interface

    • One 10/100/1000/2500 Ethernet LAN port


    • Front Panel:
      Power, Downstream, Upstream, Online, LAN
    • Rear Panel:
      The Ethernet port has two LEDs indicating data flow and LAN connection speed.
      – Green indicates 2.5 Gbps
      – Amber indicates 100 Mbps or 1 Gbps
      – Blinking indicates data flow


    • 7 7⁄8" tall x 7 1⁄4" deep x 2 1⁄4" wide
      (200 mm x 184 mm x 57 mm)


    • 18.4 ounces (523 grams)

    Power Adapter

    • DoE-compliant Level VI energy-saving, UL-listed power adapter with 12 Volt DC, 1.5 Amp output and 100-240VAC universal input
    • NEMA 1-15 (North American style) 2-prong plug is provided in the US.

    Operating Temperature

    • 32° to 104° F (0° to 40° C)


    • FCC 15B, Bureau Veritas 60950-1 ITE safety, CableLabs®, cable service providers

    Surge Protection

    • Industrial-level surge & lightning protection


    • Two years

    Operating Parameters

    DOCSIS Standards

    • DOCSIS 3.1, 3.0, 2.0, 1.1


    • Data Rate:
      Up to 3,780 Mbps*
    • Bonded Channels:
      Up to 32 SCQAM (DOCSIS 3.0) or 2 OFDM (DOCSIS 3.1)
    • Frequency Range:
      108 to 1002 MHz
    • Operating Level Range:
      -15 to +15 dBmV


    • Data Rate:
      Up to 766 Mbps*
    • Bonded Channels:
      Up to 8 SCQAM (DOCSIS 3.0) or 2 OFDMA (DOCSIS 3.1)
    • Frequency Range:
      5 to 42 MHz or 5 to 85 MHz switchable
    • Operating Level Range:
      +65 dBmV (64 QAM, single channel)
      +57 dBmV (64QAM, 4-8 channels)
      +65 dBmV (16 QAM, single channel)
      +65 dBmV (OFDMA)

    Network Protocols


    Application Protocol

    • SNMP v1/v2/v3


    • Web-based management interface utility

    System Requirements

    • The cable modem must be connected to a cable modem service that uses any of the DOCSIS standards – 3.1, 3.0, 2.0, 1.1
    • The supplied power cube plugs into the most common USA power outlet.

    Package Contents

    • DOCSIS 3.1 / 3.0 Cable Modem (no built-in router or phone jacks)
    • Power Adapter (UL listed)
    • Ethernet Cable (Cat 6)
    • Velcro® Cable Tie
    • Coax Connection Tool
    • Quick Start Flyer

    * Data throughput will be reduced by network overhead. Delivered data speeds are also dependent upon the configuration and capacity of the data-over-cable service on which the MB8611 is used.

    ** This cable modem does not have a built-in wireless router and does not have telephone jacks for support of voice phone calls.

Customer Reviews

Based on 83 reviews
Scot M.
Fast speed and no more rental fees

Incredibly easy to install. I had no issues getting it to work with Comcast. I just followed the directions and activated it through the provided URL.

Jay C.
So far so good! Easy setup!

mb6811 has been rock solid for the time owned (1 month), no need to reboot, really easy setup using Xfinity app and I am getting max speeds via my WiFi mesh system. A really great modem and it was a long overdue upgrade for our home. I highly recommend this modem! Motorola has always been a trustworthy brand for Internet connectivity needs.

Jeffery L.
Quick shipping, easy connection

Modem was up and running in just a few minutes. Works great with Mediacom, even though it’s not on their “approved” list (as of Aug 2022).

Ambarish S.

Awesome product

Robert R.
The best

Excellent easy modem.