AT&T Corp. v. Excel Communications, Inc.
United States Court of Appeals for the Federal Circuit
172 F.3d 1352 (1999)
Relevant factsFree
AT&T's (plaintiff) patent covered a message-record process using a mathematical formula and caller information to calculate differential long-distance billing rates; the district court invalidated several claims as unpatentable mathematical formulas falling within the laws-of-nature exception, prompting AT&T's infringement suit against Excel (defendant) to raise the validity question on appeal.
IssueFree
Whether a patent claim for a method or process containing a mathematical formula is valid, patentable subject matter if the claim accomplishes a function the patent laws were intended to protect.
Related cases
State Street Bank & Trust Co. v. Signature Financial Group, Inc.149 F.3d 1368 (1998)Eli Lilly & Co. v. American Cyanamid Co.82 F.3d 1568 (1996)Laboratory Corporation of America Holdings v. Metabolite Laboratories, Inc.548 U.S. 124 (2006)Harvard College v. Canada (Commissioner of Patents)4 S.C.R. 45 (2002)W.L. Gore & Associates v. Garlock, Inc.721 F.2d 1540 (1983)