Consumers - T25: First Time Installation
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T25: First Time Installation

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Information

 
Question
How do I install the T25 Cable Modem for the first time?
Answer
When installing the T25 for the first time, it is required to activate the Modem for Internet access.  This document contains the following sections:
Prior to Installation
  1. Check that the following items were included with the T25 Cable Modem.  
    • Power Cord
    • Ethernet Cable
    • Quick Start Guide
    • Software License & Warranty Card
    • Support Information Card
  2. Turn off and unplug all existing routers and modems. 
     
  3. Establish cable service with Comcast by contacting 1-800-Xfinity (1-800-934-6489).
     
  4. Locate the required information to activate XFINITY Internet service.
    • Comcast Account Number
    • Phone Number
NOTE: The Comcast account number can be found on the billing statement, the Comcast app or the work order for the service.  Comcast account login credentials if it's previously created. 

 
Installation
  1. Connect the coaxial cable (not included) from the cable wall outlet or RF splitter to the Cable connector on the rear of the T25.  Tighten the connector by hand.
     
  2. Connect a telephone cable to the TEL LINE port on the phone and to the Tel1 port on the rear of the T25.

    NOTE: Contact Xfinity Consumer Support to activate the VoIP service.

     
  3. Connect the Ethernet cable to the Ethernet port on the rear of the T25 and the Ethernet port on the Wi-Fi router, PC, or laptop.
     
  4. Connect the power cord to the Power port of the rear of the T25, then plug it into an electrical wall outlet that is not controlled by a wall switch.

    NOTE: The T25 automatically powers ON when the power cord is connected.

    User-added image

     
  5. Check the front panel LEDs on the T25.  After a brief pause the Power, US/DS, and Online LEDs should light up SOLID white.

    User-added image

     
    LED IconBlinkingOn (Solid White)
    User-added imageNot applicable; LED does not blink.AC power is properly connected to the cable modem.
    User-added imageScanning for upstream (send data) and downstream (receive data) channel connection.Upstream and downstream channels are connected.
    User-added imageScanning for an Internet connection.Cable modem is connected to the network.
    User-added imageTelephone Line 1 is either off-hook or a call is in progress.Telephone service for Line 1 is connected and activated; on-hook.
    User-added imageTelephone Line 2 is either
    off-hook or a call is in progress.
    Telephone service for Line 2 is connected and activated; on-hook.
  6. The Modem is activated when the Online LED is solid white.

    NOTE: If activation is unsuccessful, contact Xfinity customer support for further assistance and provide the following information:
    • ​Modem Manufacturer
    • Model Number
    • Serial Number
    • HFC MAC ID
    • MTA MAC ID (applicable for voice service) 
    User-added image

Activation​
  1. Launch a browser such as Internet Explorer, Chrome, or Safari.  Enter register.xfinity.com and press the Enter key to access the XFINITY Activation page. 
     
  2. On the Welcome to XFINITY! page, click the Let's Get Started! button.
     
  3. On the First, we need to authenticate your account page, enter the Comcast Account Number in the Account number field.
     
  4. Enter the phone number associated with the Comcast account in the Phone number field, then click the Continue button. 

    NOTE: The Continue button changes to "Please Wait" while it directs to the next page.

     
  5. On the Set Up your username and password page, enter a username in the Username field.

    NOTE: If a previous account was created, click the Sign in with your existing username link to proceed with the activation steps.

     
  6. Enter a password in the Password field and re-enter the password in the Confirm password field.
     
  7. Click the Choose security question drop-down menu to select a security question.
     
  8. Enter an answer for the security question selected in the Answer security question field, then click the Continue button. 
     
  9. On the Your account has been created page, review the username and email address, then click the Continue button.
     
  10. On the Connection established! You're almost done page, if desired to optimize the experience with XFINITY.com set it as the browser Home Page, check mark the box.  Otherwise click the Continue button.
     
  11. The Your device is activated page will appear.  The T25 will restart and may take up to 15 minutes to complete the boot-up sequence and connect to the Internet.​

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