The asserted claims of the '907 patents require that two different "communication interfaces" or "communication systems" be available for transmission of video content. See '4,907 patent, at 7:6-21; '7,907 patent, at 7:58-8:4. For Comcast's system to infringe the final "transferring" limitation of both '907 patents, it must provide two "communication systems." Sprint argues that Comcast's system infringes this limitation because it offers users a choice between a first communication system (e.g., Remote Tune over Comcast's coaxial cable network) and a second communication system (e.g., Remote Play over the Internet). Because Sprint accuses a combination of Remote Tune and Remote Play of infringing the asserted claims, both Remote Tune and Remote Play must separately infringe. If either Remote Tune or Remote Play does not infringe, all of Sprint's infringement claims fail.