[JURIST] The US Court of Appeals for the Federal Circuit [official website] Wednesday upheld [PDF opinion] a lower court decision that Microsoft Corp. was liable for infringing on an AT&T Corp. patent for converting speech into computer code in copies of Windows operating system sold abroad. The Court said that the software giant had distributed codec technology, used to compress speech signals into data, without authorization from AT&T. In March 2004 Microsoft settled the majority of AT&T's outstanding claims [Microsoft/AT&T press statement] but the two companies could not come to an understanding on the issue of codec technology. Reuters has more.