To experience Comcast's High-Definition (HD) service, you need an HD-enabled set-top box that allows you to receive and watch HD programs. Comcast will provide this box for an additional monthly fee.
In addition, your TV Set must be "HD-ready" or "HD-Capable." Most standard TVs have 525 horizontal screen lines with the screen itself having a 4:3 ratio of width to height. High-definition television sets, by contrast, get their better picture by having either 720 or 1,080 horizontal screen lines and a 16:9 ratio, which allows you to view a larger area than regular programming. Refer to your TV set's owner's manual for reference to 1080i and 720p.
Learn more about HD service or access pricing and packages for your area.