CSIRO sued Buffalo Inc. and its US affiliate Buffalo Technology (USA) Inc. in the U.S. District Court for the Eastern District of Texas, alleging that Buffalo's products infringed its U.S. Patent 5,487,069, which concerns Wi-Fi technology relating to the transmission and modulation of wireless signals. After the district court held that Buffalo's products infringed certain claims of the patent and that those claims were valid, the district court ordered Buffalo to stop selling its allegedly infringing products in the U.S. Buffalo appealed that order to the U.S. Court of Appeals for the Federal Circuit.
On September 19, 2008, the Federal Circuit raised the issue of whether CSIRO's patent is valid and remanded the case back to the district court.
Although Buffalo believes that the appellate court implicitly vacated the injunction when it questioned the validity of CSIRO's patent, Buffalo took the additional step of asking the trial court to stay the injunction to the extent it was still in force. Buffalo expects that the trial court will, in the near future, schedule a trial on whether CSIRO's asserted patent claims are invalid and is confident that a jury will vindicate its position.