Installation
High Speed Cable Modem
Model CM400
1. Connect a coaxial cable.
Use a coaxial cable that is provided by your
cable company to connect the cable port on
the cable modem to a cable wall outlet or a
line splitter.
Note: If Charter is your cable Internet
provider, Charter recommends connecting
your cable modem directly to a cable wall
outlet. If you must use a splitter, use a
splitter that is rated at 3.5 dBmv.
Note: If Comcast Xfinity is your cable
Internet provider, Comcast Xfinity
recommends connecting your cable modem
directly to a cable wall outlet.
Package Contents
2. Connect the power adapter.
Connect the power adapter to the
cable modem and plug the power adapter
into an electrical outlet.
Wait for the Power LED
to light green.
4. Wait for the cable modem to come
online.
It takes at least 15 minutes for the
cable modem to come online on the
network.
Aer the cable modem registers with your
cable Internet service provider, the Internet
LED
lights green.
5. Set up your Internet service.
For information about how to set up your Internet service, see the other side of this
installation guide.
Note: If Comcast Xfinity is your cable Internet provider, do the following:
Launch a web browser. You are redirected to the Xfinity self-activation page. If you are
not redirected to the Xfinity self-activation page, go to
http://www.comcast.com/activate.
You must provide your Xfinity credentials during the activation process, so make sure that
your account number, account phone number, email address, and password are nearby.
If you are unable to self-activate your cable modem, call Comcast Xfinity customer
service at 1-800-XFINITY (1-800-934-6489).
3. Connect a computer to the
cable modem.
Use an Ethernet cable to connect a
computer to the Ethernet port on the
cable modem.
Power on your computer.
Cable modem
Ethernet cable Power adapter
Coaxial cable
(not included)
Power adapter
Cable modem
Ethernet cable
Attachable feet
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General
Weight and Dimensions
