Consumers - CM820A/NA: Installation Setup

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CM820A/NA: Installation Setup

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What is the basic installation process for my CM820 Cable Modem?


This document describes the installation process for the CM820 Cable Modem.

Before Installation

Before beginning the installation, check that the following items were included with the ARRIS CM820 Cable Modem.

  • Power Cord
  • Quick Installation Guide
  • Ethernet Cable
  • End User License Agreement

System Requirements

  • Hardware - The following hardware configuration (below) is the minimum recommended. Computers not meeting this configuration can still work with the CM820, but may not be able to make maximum use of CM820 throughput.
    • CPU: P4, 3GHz or faster
    • RAM: 1GB or greater
    • Hard drive: 7200 RPM or faster
    • Ethernet: Gig-E (1000BaseT)
  • Operating System
    • Ethernet connection: Windows 7,  Windows Vista,  Windows XP, or Windows 2000.   Mac OS X or Mac OS 7.5 - 9.2 (Open Transport recommended).  UNIX or Linux with the latest service packs and patches.
  • The TCP/IP Settings on the computer are setup to obtain an IP address Automatically.

Other Requirements

  • 75-ohm coaxial cable with F-type connectors is required to connect the CM820 to the nearest cable outlet.
  • Cable service must be activated with an Internet Service provider to access the Internet and other online services.


  • To avoid damaging the cable modem with static electricity, always first connect the coaxial cable to the grounded cable TV wall outlet.
  • Before connecting or disconnecting the Ethernet cable from the cable modem or PC, always touch the coaxial cable connector on the cable modem to release any static charges.
  • Postpone CM820 installation until there is no risk of thunderstorm or lighting activity in the area.
  • To avoid potential shock, always unplug the power cord from the wall outlet or other power source before disconnecting it from the CM820 rear panel.
  • To prevent overheating the CM820, do not open the unit or block the ventilation holes on the sides of the unit.
  • Wipe the cable modem with a clean, dry cloth. Never use cleaning fluid or similar chemicals. Do not spray cleaners directly on the unit or use forced air to remove dust.

To Install CM820

  1. Connect one end of the coaxial cable to the cable outlet or splitter.
  2. Connect the other end of the coaxial cable to the cable connector on the CM820.  Hand-tighten the connectors to avoid damaging them.
  3. Plug the power cord into the power connector on the CM820.
  4. Plug the power cord into the electrical outlet.  This turns on the CM820.

    NOTE 1: Allow the gateway five to thirty minutes to find and lock on the appropriate communications channels after the gateway is on.

    NOTE 2: The power cord does not need to be unplugged when the gateway is not in use.
  5. Connect one end of the Ethernet cable to the Ethernet port on the CM820.
  6. Connect the other end of the Ethernet cable to the computer.




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