Software giant Microsoft is using US copyright law to disable competing hardware on its Xbox console.

In 2009 Microsoft disabled Datel memory cards. The outfit started an antitrust lawsuit. However now it has become a test of the Digital Millennium Copyright Act.

Microsoft has a bit of case law on its side. The 1998 DMCA the movie studios asserted that part of the law to block RealNetworks from distributing DVD-copying software. Sony used it against PlayStation hacker George Hotz and the government also cited the law in its criminal prosecution of a California man for running a business modding Xboxes.

However Microsoft sells its own data cards and it was being undercut by Datel. Microsoft said that its actions were protected by the DMCA, because Datel’s memory cards are circumventing an Xbox memory card authentication sequence.

However the Electronic Frontier Foundation and Public Knowledge argued in a federal court filing that the argument was pants. It claimed that Redmond was using the DMCA to grant it exclusive rights to sell any and all Xbox-360-compatible memory cards, controllers, and headsets.

Microsoft claimed that Datel ripped off Microsoft’s authentication firmware to make its chips work.