A patentee brought an action for infringement of a patent related to video-on-demand products and services. The accused system sent two identifiers, known as the ClientID and SessionID, to its Connection Table. The jury found infringement, and the court entered a permanent injunction.

The infringer released a modified system, which sent only the SessionID to the Connection Table. The ClientID still performed the same function, but did so in a way that was non-infringing, namely, by being placed elsewhere in the modified system than in the Connection Table.

In response, the patentee filed a motion seeking to hold the infringer in contempt of the injunction. The patentee contended that the differences between the ClientID and the SessionID were not significant because the Connection Table was update with the same six-byte MAC address information that was present in both the ClientID and the SessionID. The district court disagreed, holding that the modified system was more than colorably different from the original system.

The Federal Circuit affirmed. The court emphasized the patentee’s trial theory. Specifically, the patentee had focused on the ClientID, and had not identified the MAC address as the infringing aspect of that element. The court found there were significant differences between the ClientID and the SessionID in that they were made up of different constituent numbers. Thus, the court held that “the colorable-differences standard focuses on how the patentee in fact proved infringement, not what the claims require.” Because the defendant used the ClientID in a way that no longer infringed, the modified system was colorably different.

A copy of the opinion can be found here.