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Linksys CM100


Modem Information

Cable Modem

DOCSIS 2.0 with speeds of up to 25 Mbps on a wired connection.

Cox recommends a DOCSIS 3.0 16x4 or higher modem

What does this mean?DOCSIS 2.0 has a maximum speed of 25 Mbps on the Cox network.

Highest Service Level


Front View

CM100 modem front view

Click to enlarge.

After the cable modem has successfully registered on the network, the Power, Online, and Link indicators illuminate continuously to indicate that the cable modem is online and fully operational.

Back View

Back View of CM100 modem

Click to enlarge.

The Linksys CM100 has the following ports available on the back of the modem.

    Power - Connects the cable modem to the power adapter.
  • USB - Connects to the USB port on your computer.
  • ETHERNET - Connects to the Ethernet port on your computer.
  • Reset - Used to reset the modem.
  • CABLE - Connects to the cable wall outlet.

The reset button is for maintenance purposes only.

MAC Address

MAC Address of CM100 Modem

Click to enlarge.

The information below is usually found on a sticker located on the bottom of the modem.

  • The S/N is the serial number.
  • The CM MAC is the MAC address.

MAC addresses are written as 12 digits containing both letters and numbers (0-9, A-F). A MAC address is unique. The first six characters of the MAC address are unique to the manufacturer of the device.


The lights indicate the current status of your modem. To troubleshoot any connection problems, use the table below.

Modem LightStatusProblem
POWERSolid GreenNone.
OffNo power. Verify that the power supply and electrical outlet connections are secure. Also make sure the outlet is not connected to a switch.



Slow Flashing GreenSearching for cable connection. Verify all cable connections and try resetting the modem.
Fast Flash ModemSearching for cable connection. If this is a new modem or a replacement modem, contact Cox with the MAC address. If there are several MAC addresses on the modem use the HFC or RF MAC address.
OffNo cable connection. Verify all cable connections and try resetting the modem.



Flashing GreenLooking for upstream connection. Verify all cable connections and try resetting the modem.
Solid GreenModem found connection.
ONLINESolid GreenCable modem is registered, network access enabled.
LinkSolid GreenSuccessfully found the computer through an Ethernet connection.
Flashing GreenModem is transferring data.
OffNo Ethernet found. Verify Ethernet cable connections, the TCP/IP settings and the NIC. The NIC drivers may need to be reinstalled.

Manufacturer Resources

For more detailed technical information on the CM100, use the resources below from Linksys.

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