U.K.-based telecommunications giant British Telecom (BT) is suing American video game developer and distribution platform owner Valve. The suit claims that four separate patents owned by BT are incorporated into Valve’s services, specifically citing “Steam Library, Steam Chat, Steam Messaging, and Steam Broadcasting.”

First, the “Gittens” patent “relates generally to providing users with content that originates from multiple subscription services and delivering it through a single portal where a customer may access content for which it has access rights.” This claim alludes to Steam’s ability to consolidate games not purchased initially through its service into its unified portal.

Second, the “Newton” patent pertains to “a method for delivering structured messages comprised of information and data parts to an intended audience in a reliable and predictable manner.” BT claims that Steam Chat infringes on this particular communication structure because “messages are stored as files at a server for retrieval by the intended clients. Each client transmits requests for messages to the server at automatic and periodic intervals.”

Next, the “Beddus” patent also allegedly pertains to Steam’s built-in chat and messaging system, covering “different communication mechanisms and each mechanism is associated with a call control protocol. The user’s status is monitored, and when the user is determined to be logged out of the system, persistent communication mechanisms are available and at least one non-persistent communication mechanism is unavailable.” Essentially this is referring to how Steam users’ online status can be made available to their friends, allowing for different communication options depending on whether they are logged in.

Finally, the “Buckley” patent covers a “multi-user display system and method for controlling a communal display that includes at least two independent workstations and an interface server for connection to a data network.” This alludes to Steam Broadcasting, which lets users stream games between different computers authorized by the user on a shared network.

The suit claims that BT reached out to Valve in October of 2015 with a letter summarizing these claims, and containing a detailed breakdown of each infringement, however “neither Valve’s General Counsel, nor anyone else at Valve, responded …”

Gamespot points out that the technologies in question, being somewhat broadly defined, are also integral to services like “YouTube, Twitch, Blizzard’s Battle.net platform, Apple’s App Store, and various other modern gaming and VOD services.” BT has not yet clarified why Valve in particular is its target, or whether it intends to pursue legal action against these other companies.

As an enormous, multinational conglomerate, BT is no common patent troll, which makes the prospect of going to court decidedly more intimidating.

It is also worth pointing out that BT filed the suit in the U.S. District Court of Delaware, even though Valve is based in Bellevue, Washington. The filing explains that “Valve distributes, offers for sale, sells, uses, imports and/or advertises products and services that infringe the claims of the Patents-In-Suit in the State of Delaware, and are accessible to and accessed by customers of this District, e.g., through the internet.” Due to the online and global nature of Valve’s business, however, this would be equally true in any district. BT almost certainly selected Delaware because it is second only to East Texas in being highly favorable toward patent holders.

Valve has not yet responded to the suit. We will update this story as events unfold.