HBO's Internet streaming service, which gives subscribers access to its shows on PCs, smartphones and tablets, is going back to where it all started: the TV.

HBO Go will be available on Roku's Internet set-top boxes at the end of this month, HBO and Roku said Tuesday.

The boxes, which start at $50, connect to a broadband line and display movies and TV shows from sources such as Netflix and Hulu on a TV set.

As before, HBO Go is only available for free to those who have a conventional cable subscription to HBO, a unit of Time Warner Inc.

Not all cable subscribers are eligible. For instance, subscribers with Time Warner Cable, which is separate from Time Warner Inc., don't have access because of a dispute between the cable company and HBO.

While the Roku boxes will only work for cable subscribers, they will provide a way to watch in a room where there's no conventional cable set-top box. They'll also work outside the home.

HBO Go will provide resolutions up to 720p, the lower grade of high-definition, spokeswoman Laura Young said. HBO's goal is to get the resolution up to 1080p, the best that today's TV sets can display.