Claim Differentiation Doctrine Fails To Trump Interpretation Supported By Intrinsic Evidence

In Inpro II Licensing, S.A.R.L. v. T-Mobile USA, Inc. (No. 05-1233; May 11, 2006), the Federal Circuit affirms a district court's claim construction and holding of non-infringement.  The claims at issue are directed to a digital assistant module, which includes a host interface.  The district court held that both intrinsic and extrinsic evidence limited this interface to a direct parallel bus interface, even though this limitation is not specifically recited in the claims.  The patentee objected, contending that because other, unasserted claims specifically limit the host interface to a direct-access parallel bus the doctrine of claim differentiation requires the recitation of the host interface in the claims at issue to be interpreted more broadly than a direct parallel bus interface.  Like the district court, the Federal Circuit, however, disagrees.  Noting that the patent specification disparages the serial interface that the patentee asserts the claims cover, identifies the direct parallel bus interface as a “very important feature,” fails to describe any other type of bus for the host interface, and describes a serial connection for a different bus, the Federal Circuit holds that employing different words to describe the same element does not necessarily change the scope of the claims where the surrounding evidence fails to support different interpretations.