Microsoft has lost an appeal that it infringed an AT&T patent for converting speech into computer code in its Windows operating system.
The US appeals court ruling affects copies of Microsoft Windows using the codec technology that are distributed outside the US.
Microsoft made an undisclosed settlement with AT&T over the issue in 2004, but Microsoft had claimed it was not liable for any patent infringement outside the US.
The appeals court upheld a lower court’s ruling that it was. Microsoft will now have to compensate AT&T as a result.