Comcast, Xfinity, Voice, Telephony, installation Assistant, setup, install, configure, usage, Internet, connection, activation, product overview, general 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:
Check that the following items were included with the T25 Cable Modem. Â
Power Cord
Ethernet Cable
Quick Start Guide
Software License & Warranty Card
Support Information Card
Turn off and unplug all existing routers and modems. Â
Establish cable service with Comcast by contacting 1-800-Xfinity (1-800-934-6489). Â
Locate the required information to activate XFINITY Internet service.
Comcast Account Number
Phone Number
NOTE:Â The Comcast account number can be found on the billing statement, the Comcast app or the work order for the service. Â Comcast account login credentials if it's previously created.Â
 Installation
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. Â
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. Â
Connect the Ethernet cable to the Ethernet port on the rear of the T25Â and the Ethernet port on the Wi-Fi router, PC, or laptop. Â
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 T25Â automatically powers ON when the power cord is connected.
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Check the front panel LEDs on the T25. After a brief pause the Power, US/DS, and Online LEDs should light up SOLID white.
Â
LED Icon
Blinking
On (Solid White)
Not applicable; LED does not blink.
AC power is properly connected to the cable modem.
Scanning for upstream (send data) and downstream (receive data) channel connection.
Upstream and downstream channels are connected.
Scanning for an Internet connection.
Cable modem is connected to the network.
Telephone Line 1 is either off-hook or a call is in progress.
Telephone service for Line 1 is connected and activated; on-hook.
Telephone Line 2 is either off-hook or a call is in progress.
Telephone service for Line 2 is connected and activated; on-hook.
The Modem is activated when the Online LED is solid white.
NOTE:Â 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)Â
Activation​
On your mobile device, download the Xfinity app from the App store or on Google Play. If you already have the Xfinity app, make sure to update to the latest version. Â
Open the app and sign in with your Xfinity ID. Â
Follow the steps to get online. Â
The front LEDs will be solid when it has reached this state. The modem may reboot a few times during the activation process, which is normal. Â
Activation is complete when there is solid white Internet LED. It may take up to 10 minutes before you can connect to the Internet. Â
