activate the xfinity without installing the app

Connect it to the coax line / outlet and power it up. Let it fully sync up with the system. Check that the front or the top panel indicator light(s) is / are steadily lit. 

Then connect a computer to it and open up a browser. You *may* see their *Walled Garden* modem self registration page. If so, follow the screen prompts. Have your mobile telephone number, your Xfinity username and password, or the account number and telephone number associated with your Comcast account handy.

If not, try calling 1-855-652-3446. That is their self-install device activation line.

If that doesn't work for you, you can call 1-800-comcast and tell a rep that you would like to have a new modem provisioned for service. Have the RF / CM / HFC MAC address and the serial number of it handy when you call.

Good afternoon @user_kns3x1, and happy Wednesday, we hope you are having a wonderful day so far and appreciate you taking the time to reach out to our dedicated Community Forums team. I see that your phone cannot install the app due to having a low system version and need further assistance with activating your modem. Our team can help with activating your modem so you can start enjoying your new service, rest assured, you're in good hands and have reached the right team to help! In order to activate the modem, we will first need to get the account brought up by collecting some sensitive information and then verifying the account with a security code. We'll then confirm the equipment information we have showing is correct and run through some steps on our end. We'll have you up and running as soon as possible! 

To get started, can you please send us a Direct Message with your first and last name along with the service address on the account including any unit or apartment numbers?

To send a "Direct Message" ("Private") message:

Click "Sign In" if necessary

• Click the "Direct Message chat" icon
• Click the "New message" (pencil and paper) icon
• Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line
• Type your message in the text area near the bottom of the window
• Press Enter to send it

We look forward to working with you further. 😀