Comcast XFINITY → Re: Self-install questions/problems?

How cable channels are blocked varies from city to city. Various types of filters and traps are used to block specific analog tv channels or groups of channels. Not all filters will block internet access. If these filters are present on your line they are normally “up on the pole”. This makes it very difficult for you to determine if you have them. It also means that if they are present a comcast truck roll will be required to remove them.
There are others here who are far more knowledgeable than I am as to all the methods used for channel blocking.