Issue 182 | April 9, 2004
Microsoft Corporation v.
Multi-Tech Systems, Inc. et al.

In Microsoft Corporation v. Multi-Tech Systems, Inc. et al., No. 03-1138 (Fed. Cir. February 3, 2004), the federal circuit affirmed summary judgment grants of noninfringement to Microsoft and Net2Phone of Multi-Tech's '649, '627, and '532 patents, directed to personal computer based systems and methods for simultaneously transmitting voice and/or computer data to a remote site over a telephone line.

Microsoft filed suit against Multi-Tech seeking a declaratory judgment of non-infringement, invalidity, and unenforceability of seven Multi-Tech patents. Multi-Tech counterclaimed alleging infringement of the '289, '470, '649, '627, and '532 patents. The district court construed the disputed claim terms for the two cases in a single Markman order. The district court concluded that, for all patents at issue, the intrinsic evidence limited Multi-Tech's inventions to use of a direct point-to-point telephone line connection. In both cases, the district court entered final judgments of non-infringement of the '289, '470, '649, '627, and '532 patents. Multi-Tech appealed to the Federal Circuit, challenging the judgments with respect to the '649, '627, and '532 patents.

The Federal Circuit observed that only claim 1 of the '627 patent explicitly referred to transmission over a telephone line, and that claim 1 of the ‘627 patent as well as the claims in the '649 and '532 patents were more broad and did not exclude data transmission over a packet-switched network. However, the court interpreted the claims in light of the specification, which was identical for all three patents, as directed to communications "over a standard telephone line" and not encompassing data transmission over a packet-switched network such as the internet. The court stated that the prosecution history of the '627 patent showed that Multi-Tech viewed its inventions as being limited to communications over a telephone line.

In addition, the Federal Circuit, applying Georgia-Pacific, concluded that Multi-Tech's statements made during the prosecution of the '627 patent with regard to the scope of its inventions as disclosed in the common specification were relevant not only to the '627 and '532 patents (issued after the '627 patent), but also to the earlier issued '649 patent (issued before the '627 patent).

In Georgia-Pacific, the Federal Circuit previously rejected the argument that the patentee was bound, or estopped, by a statement made in connection with a later application after the patent in suit had issued. 195 F.3d 1322, 1333 (Fed. Cir. 1999). Notwithstanding, the court stated that Georgia-Pacific did not suggest that patentee's statements would be irrelevant to the scope of the disclosed invention: "any statement of the patentee in the prosecution of a related application as to the scope of the invention would be relevant to claim construction."

The federal circuit also considered and revised the district court's claim construction of the limitations relating to "headers," "multiplexing," and "speaker phones." However, due to Multi-Tech's stipulations of non-infringement, the federal circuit ultimately affirmed the judgments of the district court.

In a colorful dissent, Judge Rader stated the majority: (1) manufactured an unreasonable limitation out of vague specification references as requiring the exclusive use of telephone line transmission; (2) stretched to find a clear and unambiguous disclaimer in the prosecution history of the '627 patent; and (3) disregarded the holding of Georgia-Pacific by applying the prosecution history of one patent to limit the claims of a related patent that was allowed before the creation of the prosecution history at issue.

To view the full decision visit http://www.aplf.org/mailer/Issue182.doc

To discuss this topic further, please feel free to contact the author Michael R. Dzwonczyk, (mdzwonczyk@sughrue.com), at Sughrue Mion, PLLC in Washington DC., USA.

The information contained in this email is provided for informational purposes only and does not represent legal advice. Neither the APLF nor the author intends to create an attorney client relationship by providing this information to you through this message.

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