From there, you can change the TV output to match the proper HDMI connection. Sorry, there is insufficient stock for your cart. I have new Vizio TV. When you receive a cable TV set-top box from Comcast, it will need to be activated before you can receive channels on it. Level up your tech skills and stay ahead of the curve. How It Works Find your TV Box below and click the appropriate link to view the user manual and other support materials. I've had two. I don't mind the extra buttons; what I do mind is how stiff they are. Select TV Output Resolution. Note: When looking at the back of the device, the HDMI port is the largest port, or the second port from the right. 7. High-Definition Multimedia Interface (HDMI) HDMI cables are a popular choice for carrying both audio and video signals to your home theater setup. Youre eligible for Xfinity Flex if you have an Internet-only subscription. Required for watching 3D video. 2. Future US, Inc. Full 7th Floor, 130 West 42nd Street, Go to https://www.xfinity.com/activate in a browser. While it has Netflix, Amazon Prime and the premium cable channels (HBO, Showtime, Epix), the biggest failing of the Flex is its extremely limited number of apps and content partners. Then, selectSoundand selectSound Output. You get thousands of free movies and shows Xfinity Flex lets you stream more than 10,000 free movies and shows from apps like Pluto, Xumo, and Tubi. Follow these steps to switch TV inputs with the supplied remote control: Press the INPUT button to display the Input source menu. DVD: Blue, Game: Red. This works on my new 70. From the top listed menu selections, scroll to the right and select Settings, then select Display & Sounds. If you're using Internet Explorer 9 or earlier, you will need to use an alternate browser such as Firefox or Chrome or upgrade to a newer version of internet Explorer (IE10 or greater). Re: Xfinity Cable Box Option from Home on ROKU. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/c\/c1\/Activate-a-Comcast-Cable-Box-Step-1-Version-2.jpg\/v4-460px-Activate-a-Comcast-Cable-Box-Step-1-Version-2.jpg","bigUrl":"\/images\/thumb\/c\/c1\/Activate-a-Comcast-Cable-Box-Step-1-Version-2.jpg\/aid1641067-v4-728px-Activate-a-Comcast-Cable-Box-Step-1-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"