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DOCSIS® 3.0 8x4

Cable Modem

Lose the Lease. Keep the Speed.

Eliminate your monthly equipment rental fees and get up to 340Mbps. Whether you're streaming or gaming, you'll enjoy faster connections and speed to spare. Compatible with cable Internet providers (ISP’s) like XFINITY® from Comcast, Spectrum, Cox, Cablevision and more.

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Model: CM400
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The NETGEAR CM400 High Speed Cable Modem provides a connection to high-speed cable Internet with speeds up to 340Mbps. It is CableLabs® certified and with DOCSIS® 3.0 is 8X faster than 2.0. A Gigabit Ethernet port provides faster access and downloads.

  • Up to 340 Mbps download and upload speed for streaming HD videos, faster downloads, and high-speed online gaming
  • CableLabs® Certified for U.S. Cable Internet Services—DOCSIS® 3.0 is 8 times faster than DOCSIS 2.0
  • Works with Cable Internet Providers like XFINITY® from Comcast, Spectrum, Cox, Cablevision & more (not compatible with cable bundled voice services)
  • Fast self-activation for XFINITY customers—Get connected without a service call
  • 8x4 Channel bonding offers the fastest possible cable Internet speeds during peak hours —8 downstream and 4 upstream channels
  • Save money over time and eliminate monthly rental fees, up to $168 per year*
  • Gigabit Ethernet port—Fastest wired speeds to connect your router or computer
Product Number
Product Thumbnail
WiFi Performance
  • Not Applicable
Product Diagram
Number of Ethernet Ports
  • One (1) Gigabit Ethernet port with auto-sensing technology
Key Features
  • Designed to meet DOCSIS 3.0 specifications and backward compatible with DOCSIS 2.0 networks
  • Channel bonding for fast download and upload speeds - (8 x 4) 343Mbps† download & 122Mbps† upload
  • Works with Cable Internet Providers like XFINITY® from Comcast, Spectrum, Cox, Cablevision & more
  • IPv6 next generation Internet addressing support
  • Gigabit Ethernet port with auto-sensing technology
  • Simple—CD-less installation
  • Memory: 8MB flash and 64MB DDR
  • IPv6 support (Internet Protocol Version 6)
System Requirements
  • Cable Broadband Internet service
  • Please check your cable Internet service provider web site for data speed tier compatibility
  • Microsoft® Windows® 7, 8, Vista®, XP, 2000, Mac OS®, or other operating systems running a TCP/IP network
  • Microsoft® Internet Explorer® 5.0, Firefox® 2.0, Safari® 1.4, or Google Chrome 11.0 browsers or higher
Physical Specifications
  • Dimensions: 5.8 x 3.8 x 1.8 in (147 x 96 x 30 mm)
  • Weight: 0.44 lb (0.19 kg)
Package Contents
  • High Speed Cable Modem—DOCSIS 3.0 (CM400)
  • Stand
  • Ethernet cable
  • Power adapter
  • Quick install guide

*Based on typical monthly equipment rental fee of $10 per month

†Maximum rate is derived from DOCSIS® 3.0 specifications and actual throughput will vary depending on the MSO provisioning and speed tier subscription. Check your cable Internet service provider web site for data speed tier compatibility. NETGEAR makes no express or implied representations or warranties about this product’s compatibility with any future standards. Customer-owned modems may not be compatible with certain cable networks. Please check with your cable provider to confirm this NETGEAR modem is allowed on your cable network. This product not compatible with Cable bundled voice services.

NETGEAR Warranty

  • This product is backed by a NETGEAR limited 1-year Hardware Warranty.
  • 24/7 basic technical support provided for 90 days from purchase date, when purchased from a NETGEAR authorized reseller.


Lose The Lease.

Is your cable ISP charging you every month just to use their modem? Reduce your bill and bring-your-own-modem. The CM400 is compatible with most major cable service providers.

Save Shelf Space.

The narrow profile of the CM400 lets you tuck it away behind other components and keeps your valuable shelf space open.