Words Matter: Main Power Source Held to Encompass Both AC and DC Power Sources

Intellectual Property Law

In Network-1 Technologies, Inc. v. Hewlett-Packard Co.,1 the Federal Circuit held the claim term “main power source” was interpreted to include both AC and DC power sources, especially where specification never described that a DC power source was an essential feature of the main power source.

Network-1 Technologies, Inc. (Network-1), sued Hewlett-Packard (HP), alleging infringement of U.S. Patent No. 6,218,930 (the ’930 patent). The ’930 patent related to systems and processes for enabling electronic devices to automatically decide whether remote equipment could receive remote power over Ethernet. A low-level current was transmitted to an access device. If the device was able to receive remote power using the low-level current, a detected voltage level would match a predetermined voltage condition. If the certain condition was sensed, the network switch increased the current from the low level to a higher level to activate the remote equipment. If the voltage condition was not detected, the network switch resolved that the device could not receive remote power and did not send a higher current.2

Claim 6 of the ’930 patent was representative and recited the following:

6. Method for remotely powering access equipment in a data network, comprising,

providing a data node adapted for data switching, an access device adapted for data transmission, at least one data signaling pair connected between the data node and the access device and arranged to transmit data therebetween, a main power source connected to supply power to the data node, and a secondary power source arranged to supply power from the data node via said data signaling pair to the access device,

delivering a low[-]level current from said main power source to the access device over said data signaling pair,

sensing a voltage level on the data signaling pair in response to the low[-]level current, and
 

controlling power supplied by said secondary power source to said access device in response to a preselected condition of said voltage level.3

The district court litigation advanced to trial and the court determined that the ’930 patent was invalid.4 The district court interpreted “main power source” as “a DC power source,” and as a result omitted AC power sources from the claimed main power source. The district court determined that the use of AC power was inoperable and interpreted “main power source” to bar such embodiments.5

On appeal, Network-1 argued that the district court incorrectly interpreted the claim term “main power source” and the Federal Circuit agreed.6 The court explained that claim terms “are generally given their ordinary and customary meaning,” which is “the meaning that the term would have to a person of ordinary skill in the art in question at the time of the invention.”7 “[T]he claims themselves provide substantial guidance as to the meaning of particular claim terms” and “the specification is the single best guide to the meaning of a disputed term.”8

Network-1 alleged that the claim phrase “main power source” should be defined using the usual interpretation of “power source,” which includes both AC and DC power sources. Network-1 conceded that some embodiments that disclosed use of an AC power source entailed power from the main power source to be converted to DC power. However, Network-1 asserted that the ’930 patent specification did not exclude AC power but actually supported an interpretation that encompassed AC and DC power sources. The Federal Circuit agreed with Network-1 and reversed the district court’s interpretation of “main power source.” The court ruled:

We conclude that the correct construction of “main power source” includes both AC and DC power sources. There is no dispute that the ordinary meaning of “power source” includes both AC and DC power sources. . . . And neither the claims nor the specification of the ’930 patent require a departure from this ordinary meaning.9

The court noted that claim 6 recited a “main power source” that was “connected to supply power to the data node” and “deliver[ed] a low[-]level current . . . to the access device.”10 The court noted that the claims did not suggest that the main power source should be limited to only a DC power source. “The specification likewise never expresses a preference for DC power sources, much less a suggestion that DC power is an ‘essential’ feature of the main power source.”11

The Federal Circuit also held that the district court incorrectly narrowed the claims to carve out specific inoperable embodiments:

To be sure, we have stated that we skeptically view a construction that renders all embodiments inoperable, but we have instructed that it is nonetheless improper to add limitations to constructions to exclude only certain inoperable embodiments.12

The district court’s interpretation not only left out inoperable embodiments that did not convert AC to DC power, but it also omitted working embodiments, including the preferred embodiment. Therefore, the court held that the district court incorrectly interpreted the claim phrase “main power source.”13

Lessons

Claim terms/words are generally given their ordinary and customary meaning, which is what one of ordinary skill in the art at the time of the invention would have understood the claim term to mean. The specification is the single best guide to the meaning of a claim term. The Federal Circuit concluded that the correct interpretation of “main power source” included both AC and DC power sources because the ordinary meaning included both types of power sources. Neither the claims nor the specification dictated a different meaning than this ordinary meaning.

Words matter in patent law: that is, words in your patent specification and patent claims. Patent specifications including the claims are to inventions as property boundaries are to real estate. If you have an incorrect description of your property boundaries, you could end up with owning less property than you think. The same applies to patents and inventions—an incorrect description, whether in the specification or claims, can result in an unnecessarily narrow or limited invention. 


Irah Donner is a partner in Manatt’s intellectual property practice and is the author of Patent Prosecution: Law, Practice, and Procedure, Eleventh Edition, and Constructing and Deconstructing Patents, Second Edition, both published by Bloomberg Law.


1 Network-1 Technologies, Inc. v. Hewlett-Packard Co., 981 F.3d 1015, 2020 USPQ2d 11390, 2020 WL 6814481 (Fed. Cir. 2020).

2 Id., 981 F.3d at 1018–19.

3 Id., 981 F.3d at 1019 (quoting U.S. Patent No. 6,218,930, claim 6).

4 Id., 981 F.3d at 1020–21.

5 Id., 981 F.3d at 1023.

6 Id., 981 F.3d at 1021.

7 Id., 981 F.3d at 1022 (quoting Phillips v. AWH Corp., 415 F.3d 1303, 1312–13, 75 USPQ2d 1321, 1326 (Fed. Cir. 2005) (en banc) (internal quotation marks and citations omitted)).

8 Id., 981 F.3d at 1022 (quoting Phillips v. AWH Corp., 415 F.3d 1303, 1314–15, 75 USPQ2d 1321, 1327 (Fed. Cir. 2005) (en banc) (internal quotation marks and citations omitted)).

9 Id., 981 F.3d at 1024 (citing Starhome GmbH v. AT&T Mobility LLC, 743 F.3d 849, 857, 109 USPQ2d 1885, 1890–91 (Fed. Cir. 2014) (“In the absence of an express intent to impart a novel meaning to claim terms, an inventor’s claim terms take on their ordinary meaning.”).

10 Id., 981 F.3d at 1024 (quoting U.S. Patent No. 6,218,930, col. 4 ll. 56–57, ll. 60–61.

11 Id., 981 F.3d at 1024 (citing GE Lighting Sols., LLC v. AgiLight, Inc., 750 F.3d 1304, 1309–10, 110 USPQ2d 1800, 1803 (Fed. Cir.2014)).

12 Id., 981 F.3d at 1025 (citing Cordis Corp. v. Medtronic Ave, Inc., 511 F.3d 1157, 1174, 85 USPQ2d 1427, 1439 (Fed. Cir. 2008)).

13 Id., 981 F.3d at 1025.

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