Netgear CM400 Manuel D’Utilisation

Turn on the computer, router, or WiFi router.

Wait for the cable modem to come online.

It takes at least 15 minutes for the cable modem to come online on the network. During 

this time, the Downstream LED 

 and Upstream LED 

 might blink.

After the cable modem registers with your cable Internet service provider, the 

Internet

 

LED 

 lights green. Even though an Internet connection is established, 

Internet service is available only after you set it up with your cable Internet provider.

For information about how to set up your Internet service, see 

You must contact your Internet provider and tell them that you are using a new cable modem.

If Comcast Xfinity is your cable Internet provider, you do not need to 
call. Just launch a web browser. You are redirected to the Xfinity 
self-activation page on which you can enter your Xfinity credentials.



Contact your cable Internet provider and inform them that you are installing a new cable 
modem that you bought from a retail store. 

Provide your cable Internet provider with the cable modem’s model number, which is 
CM400.

The cable modem is certified by all major cable Internet providers.

You can also visit your cable Internet provider’s website and follow the onscreen 
instructions to set up your Internet service.

Bright House Networks

1-866-898-9101

Cablevision

When you attempt to contact Cablevision online, you are directed to the 

Optimum web page. Optimum is a brand name of Cablevision.