How to Hook up a Comcast Phone Modem

By Ray Damon

When you become a customer of a cable broadband service provider, you will be given a cable modem to use. Comcast supplies most of its Internet customers with the Motorola Surfboard cable modem. This modem can be used for Internet access as well as VoIP phone service. It can be connected to your computer using either Ethernet or USB cables. The process for hooking up this modem is relatively easy and you can probably do it on your own without having a service technician to come to your location.

Things You'll Need

  • Motorola Surfboard modem
  • Ethernet cable
  • Phone cable
  • Internet access
  • Computer

Step 1

Situate your computer on the desk where you intend to use the modem. You will need access to the back of the computer so you can connect the cables. Locate the wall outlet that provides the cable signal and connect a cable from the outlet to the Ethernet port on the back of the computer. Push the connector all the way in until you hear a click, indicating a proper connection.

Step 2

Plug one end of the power cord into an electrical outlet or power strip. Plug the other end of the power cord into the back of the Surfboard modem. Check the front of the modem to make sure the LED lights are lit. These lights should be solid green or blinking and are labeled: Power, Receive, Send, Online and Activity (depending on the model of your Surfboard modem, the LED labels might be different). Power up your computer and open your Web browser.

Step 3

Connect one end of the Ethernet cable to the Ethernet port on the back of the Surfboard modem. Connect the other end to any available Ethernet port on your computer. Click the Windows "Start" button, then click "Control Panel." Click on "Network Connections." Double-click the "Local Area Connection" icon. Click Properties" and double-click "Internet Protocol (TCP/IP)."

Step 4

Obtain your IP address from your computer by clicking the "Start" menu, then "Run." Type "CMD and press "Enter." A new command prompt will open. Type "ipconfig" (without quotes) and press "Enter." You will see lines of information on the screen. Your IP address will look something like this: "" Click on the "Use the following IP address" button and enter your IP address. Then enter the Subnet mask -- use "" (without quotes), which is common for all PCs.

Step 5

Click on the "Use the following DNS server address." Type the DNS IP addresses into the appropriate boxes. Contact your cable service provider for this information. Make sure you enter these numbers correctly. Then click "OK." Reboot your computer and you should have access to the Internet through your surfboard modem.

Tips & Warnings

  • If you are having issues connecting to the Internet on a Windows computer, using a technique called "renewing your IP address" could resolve the problem. Open the "Start" menu, click "Run," type "cmd" in the command prompt field and press "OK." Type "ipconfig /renew" and press "Enter." Type "exit" and press "Enter." Your modem will obtain a new IP address and you should be able to connect to the Internet. If that fails, locate and press the "Reset" button on the back of the Surfboard modem. Wait a minute or two for the modem to recycle, then try accessing the Internet. If you continue to have problems, contact your cable service provider for assistance.