Opinion · Court of Appeals for the Federal Circuit

Nexstep, Inc. v. Comcast Cable Communications, LLC

Nexstep, Inc. v. Comcast Cable Commc’ns, LLC, 119 F.4th 1355 (Fed. Cir. 2024)

Type
Opinion
Court
Court of Appeals for the Federal Circuit
Jurisdiction
Federal
Date
2024-10-24
Topic
litigation

Case: 22-1815 Document: 67 Page: 1 Filed: 10/24/2024 United States Court of Appeals for the Federal Circuit ______________________ NEXSTEP, INC., Plaintiff-Appellant v. COMCAST CABLE COMMUNICATIONS, LLC, Defendant-Cross-Appellant ______________________ 2022-1815, 2022-2005, 2022-2113 ______________________ Appeals from the United States District Court for the District of Delaware in No. 1:19-cv-01031-RGA, Judge Richard G. Andrews. ______________________ Decided: October 24, 2024 ______________________ PAUL J. ANDRE, Kramer Levin Naftalis & Frankel LLP, Redwood Shores, CA, argued for plaintiff-appellant. Also represented by CHRISTINA M.

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8 opinions
Case: 22-1815   Document: 67     Page: 1    Filed: 10/24/2024




   United States Court of Appeals
       for the Federal Circuit
                 ______________________

                    NEXSTEP, INC.,
                    Plaintiff-Appellant

                            v.

    COMCAST CABLE COMMUNICATIONS, LLC,
           Defendant-Cross-Appellant
             ______________________

             2022-1815, 2022-2005, 2022-2113
                 ______________________

     Appeals from the United States District Court for the
 District of Delaware in No. 1:19-cv-01031-RGA, Judge
 Richard G. Andrews.
                 ______________________

                Decided: October 24, 2024
                 ______________________

     PAUL J. ANDRE, Kramer Levin Naftalis & Frankel LLP,
 Redwood Shores, CA, argued for plaintiff-appellant. Also
 represented by CHRISTINA M. FINN, JAMES R. HANNAH, LISA
 KOBIALKA; AARON M. FRANKEL, CRISTINA MARTINEZ,
 CARLOS J. TIRADO, New York, NY.

     THOMAS SAUNDERS, Wilmer Cutler Pickering Hale and
 Dorr LLP, Washington, DC, argued for defendant-cross-
 appellant. Also represented by AMY K. WIGMORE; WILLIAM
 F. LEE, GEORGE FANTON MANLEY, SARAH B. PETTY, Boston,
 MA; LAUREN MATLOCK-COLANGELO, New York, NY; MARY
 VIRGINIA SOOTER, Denver, CO.
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 2      NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




                  ______________________

     Before REYNA, TARANTO, and CHEN, Circuit Judges.
     Opinion for the court filed by Circuit Judge CHEN.
 Opinion concurring-in-part and dissenting-in-part filed by
                  Circuit Judge REYNA.
 CHEN, Circuit Judge.
      NexStep, Inc., (NexStep) appeals from a final judgment
 that Comcast Cable Communications, LLC, (Comcast) did
 not infringe U.S. Patent Nos. 8,885,802 (’802 patent) and
 8,280,009 (’009 patent). After construing the term “VoIP”
 in the ’802 patent, the district court granted summary
 judgment of non-infringement. The ’009 patent proceeded
 to a jury trial, and the jury found no literal infringement
 but infringement under the doctrine of equivalents.
 Following a post-trial motion by Comcast, the district court
 found NexStep’s proof inadequate and granted judgment as
 a matter of law of non-infringement of the ’009 patent. On
 appeal, NexStep argues that the district court erred in its
 construction of VoIP in the ’802 patent and further erred in
 granting Comcast’s motion for judgment as a matter of law
 for the ’009 patent. We reject those challenges and affirm
 as to both issues. In light of that disposition, we do not
 reach NexStep’s contentions related to damages or
 Comcast’s conditional cross-appeal related to validity.
                              I.
      NexStep filed suit in the United States District Court
 for the District of Delaware asserting infringement of nine
 patents, including the ’802 and ’009 patents. Following
 Markman proceedings, the district court granted summary
 judgment of non-infringement of the ’802 patent, adopting
 Comcast’s view that VoIP was a term of art with a meaning
 that excluded NexStep’s sole infringement theory. At the
 same time, the district court denied Comcast’s summary
 judgment motion relating to the ’009 patent; that motion
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC           3



 argued that the ’009 patent was ineligible under 
35 U.S.C. § 101
.
     After a jury trial for the ’009 patent, the jury found that
 the asserted patent claims were infringed under the
 doctrine of equivalents. In response to the verdict form’s
 question addressing literal infringement, the jury found
 that the ’009 patent was not literally infringed.
      Following post-trial motions under Federal Rule of
 Civil Procedure 50(b), the district court set aside the jury
 verdict and granted judgment of non-infringement as a
 matter of law, finding the evidentiary record inadequate to
 support infringement under the doctrine of equivalents.
 NexStep, Inc. v. Comcast Cable Commc’ns, LLC, No. 19-cv-
 1031, 
2022 WL 1503922
, at *7 (D. Del. May 12, 2022)
 (JMOL Decision). The district court primarily reasoned
 that the testimony of NexStep’s expert, Dr. Ted Selker, was
 too conclusory to sustain the verdict. Describing portions
 of Dr. Selker’s testimony as “word salad,” the district court
 concluded that Dr. Selker’s testimony lacked the specificity
 and analysis required by our precedent. 
Id.
 Among other
 things, the district court concluded that Dr. Selker failed to
 identify specific components in the accused products and
 failed to offer a reasoned basis for concluding that those
 specific components were equivalent to the relevant claim
 limitations. 
Id.
 at *5–7. Thus, the court entered final
 judgment of non-infringement with respect to the ’802 and
 ’009 patents. The final judgment further reflected the
 district court’s summary judgment ruling rejecting
 Comcast’s affirmative defense that the ’009 patent is
 ineligible under 
35 U.S.C. § 101
.
     NexStep appeals, and Comcast conditionally cross-
 appeals. We have jurisdiction over NexStep’s appeal under
 
28 U.S.C. § 1295
(a)(1), and we do not reach Comcast’s
 cross-appeal.
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 4       NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




                              II.
                              A.
      The ’802 patent is directed to a “digital butler” that
 controls consumer electronics based on audio data. ’802
 patent Abstract; 
id.
 col. 16 ll. 20–30. Broadly speaking, the
 digital butler relies on two components: a handheld device
 capable of receiving audio input and a separate “master
 device” (or console)1 for processing that input. The audio-
 controlled handheld device “needs only limited computing
 capabilities” because it is “tethered” to the more robust
 master device supporting it. 
Id.
 claim 7, col. 1 ll. 34–43,
 col. 2 ll. 56–63. The ’802 patent describes its handheld
 device as a “remote control,” which “may resemble a
 handheld personal computer (HPC), a palm-held personal
 computer (PPC or PDA) or a smart phone.” 
Id.
 Title, col. 1
 ll. 39–41.
      Several of the claims—including claims 1 and 7, the
 only claims at issue in this appeal—further specify how the
 audio data must be processed in the claimed system. Claim
 1 is representative:
     1. A remote control device with slaved audio input,
     the device including:
     a wireless link transceiver;
     at least one slaved audio input built into the
     remote control;
     a navigation control built into the remote control;




     1   The specification uses the phrase “console” and
 “master device” interchangeably, as do the parties in their
 briefing before us.
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC          5



     hardware resources coupled between the wireless
     link transceiver, the slaved audio input and the
     navigation control;
     a stack running on the hardware resources and
     exchanging packets with a master device; and
     an encoder logic running on the hardware
     resources, logically coupled to the stack, adapted to
     encode signals from the slaved audio input into a
     remote control audio format, and adapted to send
     audio packets in the remote control audio format to
     the master device;
     wherein the remote control depends on the master
     device to transcode input from the slaved audio
     input to VoIP from the remote control device format
     and relies on the master device to respond to
     control signals sent by the remote control device in
     the packets.
 
Id.
 claim 1 (emphasis added). Claim 1 requires that the
 remote control can “encode” the audio data from a user’s
 voice into “a remote control audio format,” and that the
 remote can “send audio packets in the remote control audio
 format to the master device.” 
Id.
 Then, the master device
 performs a further conversion on the audio packets: “the
 remote control depends on the master device to transcode”
 the audio input “from the remote control device format” to
 “VoIP.” 
Id.
 Finally, the master device “respond[s] to control
 signals sent by the remote control device in” the audio
 packets. 
Id.
 In short, the remote control can receive audio
 data and transmit it to the master device, and—after
 transcoding the audio data to VoIP—the master device can
 decide how to respond to that audio data and acts
 accordingly. 
Id.
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 6       NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




                              B.
     The term “VoIP” forms the basis of NexStep’s appeal for
 the ’802 patent. The district court2 construed VoIP in light
 of the parties’ agreement that VoIP is a well-established
 term of art within the relevant industry. Specifically, the
 parties “agreed that [VoIP] is an industry standard term,
 and the patentee did not deviate from the plain and
 ordinary meaning of the term as understood by a person of
 ordinary skill in the art.” NexStep, Inc. v. Comcast Cable
 Commc’ns, LLC, No. 19-cv-1031, 
2020 WL 6375575
, at *10
 (D. Del. Oct. 30, 2020) (Markman Op.); see also, e.g.,
 J.A. 2930 (NexStep arguing that “VoIP stands for Voice
 Over Internet Protocol,” which is “a well-known protocol to”
 a skilled artisan.). Given this agreement, the district court
 turned to extrinsic “[e]vidence of the industry standard
 definition for VoIP.” Markman Op., 
2020 WL 6375575
, at
 *10.
     Based on the extrinsic evidence, the district court
 construed “VoIP” as “protocols and data formats for
 transmitting voice conversations over a packet-switched
 network, such as the Internet.” 
Id.
 (emphasis added). The
 district court rejected NexStep’s broader construction,
 which covered any “audio data,” and instead relied on
 several technical dictionaries that defined VoIP as


     2    The district court referred claim construction
 proceedings to a magistrate judge, who issued a report and
 recommendation addressing the meaning of VoIP. NexStep,
 Inc. v. Comcast Cable Commc’ns, LLC, No. 19-cv-1031,
 
2020 WL 6375575
, at *10–11 (D. Del. Oct. 30, 2020). The
 district court adopted the report and recommendation in
 full with respect to the term VoIP. See NexStep, Inc. v.
 Comcast Cable Commc’ns, LLC, No. 19-cv-1031, 
2021 WL 3489983
, at *1 (D. Del. Aug. 9, 2021). We refer to the
 opinions by the magistrate judge and district court judge
 collectively as the district court’s opinion.
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC         7



 specifically transmitting “voice conversations” in a manner
 analogous to conventional telephone calls. 
Id.
 at *10–11.
     Comcast moved for summary judgment of non-
 infringement because its accused Voice Remote products
 did not infringe the VoIP limitation under the district
 court’s construction. In considering the motion, the district
 court noted that the factual operation of Comcast’s accused
 Voice Remotes was not disputed. NexStep, Inc. v. Comcast
 Cable Commc’ns, LLC, No. 19-cv-1031, 
2022 WL 911252
, at
 *2 (D. Del. Mar. 29, 2022) (Summary Judgment Op.). The
 parties agreed that each Voice Remote captures voice
 commands from a user (for example, “turn the television to
 channel 5”) and that the set-top box sends the captured
 audio to Comcast’s servers, using a type of protocol called
 HTTP.
     Importantly, in its summary judgment briefing to the
 district court, NexStep did “not suggest that [Comcast’s]
 accused products are capable of two-way voice
 conversations.” NexStep, Inc. v. Comcast Cable Commc’ns,
 LLC, No. 19-cv-1031, 
2021 WL 4077778
, at *9 (D. Del. Aug.
 20, 2021) (Summary Judgment R. & R.). NexStep
 identified no evidence that the accused products used a
 protocol    configured    to     send   two-way      audio
 communications. Instead, NexStep argued that the VoIP
 limitation could be met by a protocol capable of only one-
 way audio transmission, contrary to Comcast’s assertion
 that VoIP, as construed by the district court, required
 capability for two-way voice conversations. See, e.g., J.A.
 8475–76 (NexStep’s summary judgment briefing).
     The district court agreed with Comcast’s view. See
 Summary Judgment Op., 
2022 WL 911252
, at *2. The
 court again rejected NexStep’s attempt to broaden the
 meaning of VoIP to cover a protocol for any transmission of
 audio data, instead agreeing that “voice conversations”
 required capability for two-way communication.          
Id.
 Because NexStep’s opposition to summary judgment
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 8      NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 hinged on its claim construction arguments, the district
 court found no genuine dispute of material fact.
 Accordingly, it granted summary judgment of non-
 infringement of the asserted claims of the ’802 patent.
                              C.
     “We review a district court’s grant of summary
 judgment according to the law of the regional circuit.”
 Amgen Inc. v. Sandoz Inc., 
923 F.3d 1023, 1027
 (Fed. Cir.
 2019). Here, we apply the law of the Third Circuit, which
 reviews “a district court’s grant of summary judgment de
 novo, applying the same standard the district court
 applied.” Viera v. Life Ins. Co. of N. Am., 
642 F.3d 407, 413
 (3d Cir. 2011). We apply Federal Circuit law to substantive
 questions of patent law, including claim construction.
 Powell v. Home Depot U.S.A., Inc., 
663 F.3d 1221, 1228
 (Fed. Cir. 2011).
     “Claim construction requires determining how a skilled
 artisan would understand a claim term ‘in the context of
 the entire patent, including the specification.’” Grace
 Instrument Indus., LLC v. Chandler Instruments Co., 
57 F.4th 1001, 1008
 (Fed. Cir. 2023) (quoting Phillips v. AWH
 Corp., 
415 F.3d 1303, 1313
 (Fed. Cir. 2005) (en banc)). “We
 review claim construction based on intrinsic evidence de
 novo and review any findings of fact regarding extrinsic
 evidence for clear error.” Id.; see also Teva Pharms. USA,
 Inc. v. Sandoz, Inc., 
574 U.S. 318
, 332–33 (2015); Fed. R.
 Civ. P. 52(a)(6). Under the clear-error standard, we defer
 to the district court’s findings “in the absence of a definite
 and firm conviction that a mistake has been made.” Par
 Pharm., Inc. v. Eagle Pharms., Inc., 
44 F.4th 1379, 1383
 (Fed. Cir. 2022) (citation omitted).
     In general, the specification is the “single best guide to
 the meaning of a disputed term” and “is, thus, the primary
 basis for construing the claims.” Grace Instrument, 
57 F.4th at 1008
 (citations omitted). But extrinsic evidence
 takes on particular importance when construing a term
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC           9



 that skilled artisans recognized as a term of art at the
 relevant time. Phillips permits courts to consider extrinsic
 evidence to determine whether a claim term was, in fact,
 recognized as a term of art. 
415 F.3d at 1318
 (indicating
 that courts may rely on extrinsic evidence “to establish that
 a particular term in the patent or the prior art has a
 particular meaning in the pertinent field”). If the court
 finds that the relevant skilled artisans understood the
 phrase as a term of art, then the court may make factual
 findings as to what meaning a skilled artisan would ascribe
 to that term. Teva, 574 U.S. at 331 (explaining that
 sometimes “the district court will need to look beyond the
 patent’s intrinsic evidence and to consult extrinsic evidence
 in order to understand . . . the meaning of a term in the
 relevant art during the relevant time period”). The court
 must focus its analysis on the term’s meaning “as of the
 effective filing date of the patent application.” Phillips, 
415 F.3d at 1313, 1318
; Teva, 574 U.S. at 331.
                               D.
     NexStep fails to show that the district court clearly
 erred by construing VoIP to require capability for two-way
 voice communications.
     The district court’s construction is supported by its
 reliance on two technical dictionaries, which defined VoIP
 to require voice conversations. The first dictionary—
 Newton’s Telecom Dictionary—defined VoIP as “[t]he
 technology used to transmit voice conversations over a data
 network.” Markman Op., 
2020 WL 6375575
, at *10
 (quoting J.A. 2998). Similarly, the Dictionary of Computer
 and Internet Terms defined VoIP as “the transmission of
 voice telephone conversations through the Internet or
 through IP networks.” 
Id.
 (quoting J.A. 3003).
     These definitions are consistent with the district
 court’s construction and support a two-way voice
 communication requirement. Both dictionaries liken VoIP
 to other forms of telephony, such as cellular calls and
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 10     NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 landline calls, which are two-way voice communication
 systems. The association between VoIP and other forms of
 telephony reasonably supports the inference that VoIP is
 also a two-way voice communication system. Given this
 evidence, the district court had a sufficient basis for its
 construction.
     NexStep’s principal rebuttal is that Newton’s
 dictionary supports NexStep’s view by indicating that VoIP
 includes “voice emails.” NexStep reasons that if VoIP
 includes voice emails, a one-way communication, then the
 district court clearly erred in limiting VoIP to two-way
 communications.
     The district court considered and rejected this
 argument because Newton’s dictionary “confirms that VoIP
 protocols must be capable of facilitating ‘phone calls’ and
 may include additional new services such as voice emails.”
 Summary Judgment Op., 
2022 WL 911252
, at *2 (emphasis
 added) (citation omitted). In other words, the district court
 read Newton’s dictionary as discussing “voice emails” as a
 supplemental service, and the district court did not clearly
 err in its reading of the dictionary definition.
     Similarly, the district court did not clearly err in
 rejecting the testimony of NexStep’s expert, Dr. Selker.
 The sole source cited by Dr. Selker undermined his claim
 that VoIP is broad enough to cover all audio data
 transmission by explaining that “VoIP is a category of
 technologies that route real-time voice conversations over
 the internet.” Markman Op., 
2020 WL 6375575
, at *10–11.
 That Dr. Selker’s underlying evidence contradicted his
 opinion testimony provided ample basis for the district
 court to reject the testimony. Accordingly, the district court
 did not clearly err in this respect either.
                              E.
     For the first time on appeal, NexStep asserts the ’802
 patent adopted an unconventional definition of VoIP that
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC          11



 departs from its established meaning. Appellant’s Br. 56
 (arguing that the “scope VoIP was given in NexStep’s
 patents” is broad enough to cover one-way audio
 transmission).
      NexStep never made that argument below, and instead
 affirmatively asserted the opposite view by contending that
 the established meaning of VoIP controlled the
 interpretation of the term. See supra Section II.B. The
 district court expressly relied on NexStep’s representations
 in construing VoIP in accord with its industry standard
 meaning at the relevant time. Markman Op., 
2020 WL 6375575
, at *10. Based on these representations, NexStep
 forfeited any argument that the ’802 patent redefined VoIP
 to differ from its industry standard meaning.
     Nevertheless, we note that NexStep’s contentions
 about the intrinsic evidence are plainly incorrect. The
 written description repeatedly associates VoIP with
 telephony services that require capability for two-way voice
 communications. For example, the written description
 describes a list of hardware and software features that are
 “within the scope of this disclosure for providing services
 described” and lists as the first entry of such services,
 “Communication, including Phone (LL/Cell/IP).”           ’802
 patent col. 20 ll. 11–13, 39–41.3 This reference to “[p]hone”
 services, followed by three subtypes of phone service
 (landline, cellular, and VoIP), suggests that the written


     3     The specification makes clear that when “IP” is
 referred to in conjunction with “landline” and “cellular”
 services, it means VoIP. See, e.g., ’802 patent col. 18 l. 65 –
 col. 19 l. 2 (explaining that the master console may connect
 to a landline-based “telephone system,” “to a cellular or
 similar telephone system[,] or to a voice over IP (VoIP)
 system”); 
id.
 col. 20 ll. 11–13, 20 (listing “Voice
 (Landline/cell/IP)” as a “feature[] . . . within the scope of
 this disclosure”).
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 12      NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 description understood VoIP as a type of phone service akin
 to those that support two-way voice conversations. And
 when describing how the claimed master device can
 communicate externally, the ’802 patent explains that it
 may connect to (1) a conventional landline telephone
 system, (2) “a cellular or similar telephone system,” or
 (3) “a voice over IP (VoIP) system.” 
Id.
 col. 18 l. 65 – col. 19
 l. 2. These portions of the written description are
 consistent with the district court’s findings about the
 established meaning of VoIP. NexStep has identified
 nothing in the written description to the contrary.
     Indeed, the sole portion of the written description cited
 by NexStep is inapposite. NexStep argues that the written
 description equates VoIP with one-way communication
 tools, such as “dictation” or “note taking.” Appellant’s Br.
 56. But the written description simply does not equate
 VoIP with those tools. The relevant portion provides:
      In a fifth embodiment, the remote is emphasized.
      One aspect of the remote is to provide a complete
      I/O platform in the palm of the user’s hand.
      Features adaptable to VoIP and/or video phone
      operation, such as a microphone, can be used for
      other purposes, such as dictation, note taking, voice
      messaging, listening to music or remote viewing
      video.
 ’802 patent col. 3 ll. 58–63 (emphases added). As the
 district court correctly observed, this passage merely notes
 that hardware components used in VoIP conversations—
 “such as a microphone”—can also be used for “other
 purposes” (such as dictation). Id.; Markman Op., 
2020 WL 6375575
, at *11. Nothing in this paragraph redefines VoIP
 to encompass protocols not capable of supporting two-way
 communication.
     NexStep also presses an argument based on the
 doctrine of claim differentiation. Specifically, NexStep
 asserts that the inclusion of an audio-output limitation in
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC       13



 unasserted, independent claim 4 of the ’802 patent implies
 that VoIP, as used in claims 1 and 7, must not require
 capability for two-way communication. See Appellant’s Br.
 57. However, “we have been cautious in assessing the force
 of      claim         differentiation      in     particular
 settings, . . . discounting it where it is invoked based on
 independent claims.” Atlas IP, LLC v. Medtronic, Inc., 
809 F.3d 599, 607
 (Fed. Cir. 2015). We are unconvinced that
 construing VoIP to require capability for two-way
 communication renders superfluous claim 4’s requirement
 for an audio output, particularly because claim 4 does not
 even recite a VoIP limitation. See also Andersen Corp. v.
 Fiber Composites, LLC, 
474 F.3d 1361, 1370
 (Fed. Cir.
 2007) (declining to apply claim differentiation where “there
 are numerous other differences varying the scope of the
 claimed subject matter”).4
                              F.
     Finally, NexStep argues that even if we agree with the
 district court’s construction of VoIP, we should remand for
 a trial on infringement because NexStep showed genuine
 disputes of material fact even under the court’s clarified
 construction.
     NexStep forfeited this argument by failing to present it
 to the district court. “We have regularly stated and applied
 the important principle that a position not presented in the



     4    NexStep’s reply brief raises additional claim
 differentiation arguments, including as to other
 independent claims of the ’802 patent and claims of other
 patents. Arguments not raised in an opening brief are
 forfeited. Stinson v. McDonough, 
92 F.4th 1355
, 1362 n.5
 (Fed. Cir. 2024). In any event, for the same reasons, we
 remain unpersuaded that affording VoIP its industry
 standard meaning would render superfluous the audio
 output limitations of these claims.
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 14     NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 tribunal under review will not be considered on appeal in
 the absence of exceptional circumstances.” In re Google
 Tech. Holdings LLC, 
980 F.3d 858
, 863 (Fed. Cir. 2020).
 Before the district court, NexStep opposed summary
 judgment by arguing that one-way audio transmissions
 satisfied the district court’s construction of VoIP. See supra
 Section II.B. As a result, the magistrate judge explained
 her understanding that NexStep “does not suggest that
 Defendant’s accused products are capable of two-way voice
 conversations.” Summary Judgment R. & R., 
2021 WL 4077778
, at *9. And the district court judge characterized
 NexStep’s summary judgment briefing as instead
 “advanc[ing] several claim construction arguments” about
 the meaning of VoIP and the best understanding of the
 court’s Markman order. Summary Judgment Op., 
2022 WL 911252
, at *2.
     NexStep’s briefing to this court gives us no basis to
 disagree with the district court’s characterization of the
 arguments before it. NexStep failed to identify anything in
 the record asserting that Comcast’s accused products use a
 protocol configured to send two-way voice conversations.
 Indeed, NexStep’s reply brief points to evidence NexStep
 cited below that was expressly premised on the assertion
 that one-way communications are sufficient to infringe.
 See, e.g., Appellant’s Reply Br. 33 (citing J.A. 9062).
 Accordingly, NexStep forfeited this argument.
     For the reasons explained above, we affirm the district
 court’s construction of VoIP and affirm its grant of
 summary judgment of non-infringement of the asserted
 claims of the ’802 patent.
                              III.
     The second principal issue on appeal relates to the
 district court’s disposition of the ’009 patent. For the
 reasons that follow, we agree that the district court
 correctly granted Comcast’s motion for judgment as a
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC         15



 matter of law of non-infringement under the doctrine of
 equivalents.
                              A.
     The ’009 patent is directed to a “concierge device” that
 offers a streamlined approach for initiating technical
 customer support. ’009 patent Abstract. With the advent
 of the “Internet of things,” the ’009 patent observed that
 customers were increasingly swapping out traditional
 home appliances in favor of smart devices. 
Id.
 col. 2 ll. 14–
 27. This changeover of devices created an “opportunity for
 innovation” to enhance the customer service experience by
 allowing consumers to more easily and efficiently control
 and support the interconnection of consumer devices with
 services outside of the home.           
Id.
 col. 2 ll. 28–41.
 Specifically, the ’009 patent discusses a concierge device
 that initiates technical support in response to only “a single
 action” of the user. 
Id.
 Abstract. The parties agree that the
 point of novelty for the claimed invention is initiating a
 customer service support session through just a “single
 action,” saving the user time and the hassle of all the steps
 inherent in calling a support center and having to provide
 the model, serial number, or other information to identify
 what products are malfunctioning.
    Claim 1 is illustrative for purposes of the issues on
 appeal. It provides:
     1. A method of initiating a support session for a
     consumer device using a concierge device, the
     method including:
     associating the concierge device with a selected
     consumer device;
     responsive to a single action performed by a user,
     the concierge device communicating with a home
     gateway, including
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 16     NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




         causing the home gateway to buffer
         consumer device identification information
         for the selected consumer device and
         determine a support center for a support
         session; and
         causing the home gateway to initiate the
         support session for the consumer device
         and to forward automatically the consumer
         device identification information during
         the support session, thereby allowing the
         support session either
             to bypass an automated attendant
             or interactive voice recognition
             system or
             to initiate an automated support
             protocol.
 ’009 patent claim 1 (emphasis added).
     According to claim 1, when a troubleshooting issue
 arises, all the claimed steps must occur “responsive to a
 single action performed by a user.” See, e.g., ’009 patent
 claim 1 (emphasis added). That “single action” could be,
 for example, “a single press of a button,” a “shake of the
 device,” or a “spoken response.” 
Id.
 col. 4 l. 65 – col. 5 l. 3;
 see also 
id.
 col. 11 ll. 18–21 (describing a “dedicated button”
 used to initiate a support call).
     Following the user’s “single action,” the concierge
 device of claim 1 responds by taking four specific
 “troubleshooting” steps to initiate a personalized customer
 support session. First, the concierge device conveys
 “consumer device identification information” for the
 product at issue. Second, the concierge device identifies an
 appropriate technical team to support the relevant product
 by “determin[ing] a support center” that can offer a
 “support session” for the user’s device. Third, the concierge
 device causes the home gateway to initiate the support
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC        17



 session for the consumer device. Fourth, the concierge
 device causes the home gateway to automatically forward
 the consumer device information during the support
 session.
      As a result, the ’009 patent discloses a user-friendly,
 streamlined system that bypasses the need for a user to
 undertake a series of actions before a support session can
 begin and instead “allows the user in a single action to
 initiate a support call without requiring the user” to engage
 in any additional steps before receiving technical support.
 
Id.
 col. 5 ll. 20–25 (emphasis added).          The claimed
 invention is thus directed to minimizing a user’s
 interaction with a device to just one action to initiate a
 support session.
                              B.
     Before the district court, NexStep asserted that three
 different tools in Comcast’s mobile smartphone application
 (My Account App) infringed claims 1, 16, and 22 of the ’009
 patent.     The first tool is the “XfinityAssistant,” an
 interactive chatbot that can help customers with services
 related to the customer’s account, billing, privacy, and
 troubleshooting. The second tool is a “Troubleshooting
 Card,” which triggers a multi-step process for
 troubleshooting a given device associated with the
 customer’s Comcast account. And the third tool is the
 “Diagnostic Check,” which allows a user to investigate
 whether a particular device has detectable issues.
 Initiating each of these three tools requires a user to press
 a series of buttons on the smartphone’s display.5



     5   The parties dispute on appeal how many individual
 steps are involved for each of the accused tools. We note
 that Dr. Selker’s doctrine-of-equivalents testimony
 assumed the tools require “several button presses.”
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 18     NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




     At trial, the parties’ dispute focused heavily on the
 “single action” limitation. Comcast argued that the
 multiple actions—the several user button presses—
 required as a predicate to using any of the three
 troubleshooting tools meant that the My Account App did
 not infringe. NexStep focused its infringement theory on
 the view that a series of steps, when taken together, can be
 appropriately described as a single action. See, e.g.,
 J.A. 460 at 443:24–445:4 (arguing that “multiple steps
 might be contained in a single action”). Thus, NexStep
 argued, even if using each of the three accused tools
 involved multiple steps, those steps should be understood
 as a single action.
     The jury returned a verdict of no literal infringement
 (thus necessarily rejecting NexStep’s view that the series
 of user steps needed for each of the accused tools amounted
 to “a single action”) but found infringement under the
 doctrine of equivalents.      JMOL Decision, 
2022 WL 1503922
, at *1. Following trial, both parties moved for
 judgment as a matter of law:            NexStep for literal
 infringement and Comcast for non-infringement under the
 doctrine of equivalents.       The district court denied
 NexStep’s motion, and it granted Comcast’s motion because
 NexStep failed to offer the particularized testimony and
 linking argument required by our precedent for a doctrine
 of equivalents case.
     NexStep appeals. It challenges only the district court’s
 decision to set aside the infringement verdict under the
 doctrine of equivalents; NexStep does not challenge the
 denial of judgment as a matter of law of literal
 infringement.




 J.A. 445 at 383:25–384:10. The actual number of button
 presses is not material to our analysis for the reasons given
 below.
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC         
19 C. 1
.
      Judgment as a matter of law is appropriate if “the
 court finds that a reasonable jury would not have a legally
 sufficient evidentiary basis to find for the party on that
 issue.” Fed. R. Civ. P. 50(a)(1). The Third Circuit reviews
 de novo a district court’s grant of judgment as a matter of
 law, viewing the record evidence in the light most favorable
 to and drawing all reasonable inferences in favor of the
 verdict winner. Pitts v. Delaware, 
646 F.3d 151, 155
 (3d Cir.
 2011).
                               2.
      “Patent infringement is principally determined by
 examining whether the accused subject matter falls within
 the scope of the claims” as literally written. Eli Lilly & Co.
 v. Hospira, Inc., 
933 F.3d 1320, 1330
 (Fed. Cir. 2019). But
 “[t]he doctrine of equivalents provides a limited exception
 to the principle that claim meaning defines the scope of the
 exclusivity right in our patent system.” VLSI Tech. LLC v.
 Intel Corp., 
87 F.4th 1332, 1341
 (Fed. Cir. 2023). “The
 limits reflect a familiar balance among the importance of
 preserving the public’s ability to rely on claims’ meaning to
 define patent scope, the ability of patentees to protect their
 inventions through their claim drafting, and (yet) the
 occasional need to recognize some non-literal scope of
 protection to avoid undermining the exclusivity rights
 authorized by Congress to incentivize certain innovations.”
 
Id. at 1342
. A finding of infringement under the doctrine
 of equivalents is “exceptional,” Honeywell International,
 Inc. v. Hamilton Sundstrand Corp., 
523 F.3d 1304, 1313
 (Fed. Cir. 2008), and “[w]e have emphasized . . . that the
 doctrine of equivalents is the exception, however, not the
 rule,” Eli Lilly, 
933 F.3d at 1330
 (internal quotation marks
 omitted).
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 20     NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




     Under the doctrine of equivalents, “a product or process
 that does not literally infringe upon the express terms of a
 patent claim may nonetheless be found to infringe if there
 is ‘equivalence’ between the elements of the accused
 product or process and the claimed elements of the
 patented invention.” Warner-Jenkinson Co. v. Hilton
 Davis Chem. Co., 
520 U.S. 17, 21
 (1997) (citing Graver
 Tank & Mfg. Co. v. Linde Air Prods. Co., 
339 U.S. 605, 609
 (1950)). Typically, patentees seek to prove infringement
 under the doctrine of equivalents in one of two ways.
 Mylan Institutional LLC v. Aurobindo Pharma Ltd., 
857 F.3d 858, 866
 (Fed. Cir. 2017). One way, often referred to
 as the function-way-result test, asks “whether the accused
 product performs ‘substantially the same function in
 substantially the same way to obtain the same result.’” 
Id.
 (quoting Graver Tank, 
339 U.S. at 608
). And the other way
 asks whether “differences between the claimed invention
 and the accused device or process are ‘insubstantial.’” Tex.
 Instruments Inc. v. Cypress Semiconductor Corp., 
90 F.3d 1558
, 1563–64 (Fed. Cir. 1996). “Different linguistic
 frameworks may be more suitable to different cases,
 depending on their particular facts,” but these
 formulations all aim to investigate the same “essential
 inquiry.” Warner-Jenkinson, 
520 U.S. at 40
.
      Regardless of how the test is phrased, courts must
 employ “special vigilance” to avoid overbroad applications
 of the doctrine of equivalents. 
Id.
 “There can be no denying
 that the doctrine of equivalents, when applied broadly,
 conflicts with the definitional and public-notice functions
 of the statutory claiming requirement.” 
Id. at 29
. We have
 accordingly imposed “specific evidentiary requirements
 necessary to prove infringement under the doctrine of
 equivalents.” Tex. Instruments, 
90 F.3d at 1566
.
     First, proof under the doctrine of equivalents must be
 on a limitation-by-limitation basis: “[T]he doctrine of
 equivalents must be applied to individual elements of the
 claim, not to the invention as a whole.” Warner-Jenkinson,
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC        21



 
520 U.S. at 29
. This requirement means that equivalency
 is determined by comparing “the elements of the accused
 product or process and the claimed elements of the
 patented invention.” 
Id.
 at 21 (citing Graver Tank, 
339 U.S. at 609
); see also VLSI, 87 F.4th at 1344–45.
     Second, “both the Supreme Court and this court have
 made clear that the evidence of equivalents must be from
 the perspective of someone skilled in the art, for example
 through testimony of experts or others versed in the
 technology; by documents, including texts and treatises;
 and, of course, by the disclosures of the prior art.” AquaTex
 Indus., Inc. v. Techniche Sols., 
479 F.3d 1320, 1329
 (Fed.
 Cir. 2007) (cleaned up). “[W]hen the patent holder relies
 on the doctrine of equivalents,” we “require that evidence
 be presented to the jury or other fact-finder through the
 particularized testimony of a person of ordinary skill in the
 art, typically a qualified expert.” 
Id.
     Third, and most relevant to this appeal, “we have long
 demanded specificity and completeness of proof as crucial
 to enforcing the limits on the doctrine: The patentee must
 provide particularized testimony and linking argument as
 to the insubstantiality of the differences between the
 claimed invention and the accused device.” VLSI, 
87 F.4th at 1343
 (internal quotation marks and citations omitted).
 “Generalized testimony as to the overall similarity between
 the claims and the accused infringer’s product or process
 will not suffice.” Tex. Instruments, 
90 F.3d at 1567
.
 Rather, the patentee must provide a “meaningful
 explanation of why” the element or elements from the
 accused product or process are equivalent to the claimed
 limitation. VLSI, 
87 F.4th at 1344
; see also Malta v.
 Schulmerich Carillons, Inc., 
952 F.2d 1320
, 1327 n.5 (Fed.
 Cir. 1991) (Our precedent “at least requires the evidence to
 establish what the function, way, and result of both the
 claimed device and the accused device are, and why those
 functions, ways, and results are substantially the same.”).
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 22     NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




     “Our court set forth these evidentiary requirements in
 those earlier cases because, although the standard for
 infringement under the doctrine of equivalents is simple to
 articulate, it is conceptually difficult to apply.” Tex.
 Instruments, 90 F.3d at 1566–67. “These evidentiary
 requirements assure that the fact-finder does not, under
 the guise of applying the doctrine of equivalents, erase a
 plethora of meaningful structural and functional
 limitations of the claim on which the public is entitled to
 rely in avoiding infringement.” Id. at 1567 (internal
 quotation marks and citation omitted). Plus, “without
 these requirements, the fact-finder has no analytical
 framework for making its decision and is put to sea without
 guiding charts when called upon to determine
 infringement under the doctrine,” and “we, as the
 reviewing court, would lack the assurance that the jury
 was fully presented with a basis for applying the doctrine
 of equivalents.” Id. (cleaned up).
     Though “we do not doubt the ability of a jury to decide
 the factual issue of equivalence, to enable the jury to use
 its ability,” the patentee’s case “must be presented in the
 form of particularized testimony and linking argument.”
 Lear Siegler, Inc. v. Sealy Mattress Co. of Mich., 
873 F.2d 1422, 1426
 (Fed. Cir. 1989).            These evidentiary
 requirements therefore serve to “ensure that a jury is
 provided with the proper evidentiary foundation from
 which it may permissibly conclude that a claim limitation
 has been met by an equivalent.” Comark Commc’ns, Inc. v.
 Harris Corp., 
156 F.3d 1182, 1188
 (Fed. Cir. 1998).
     So though “[a] finding of equivalence is a determination
 of fact,” Graver Tank, 
339 U.S. at 609
, “the various legal
 limitations on the application of the doctrine of equivalents
 are to be determined by the court, either on a pretrial
 motion for partial summary judgment or on a motion for
 judgment as a matter of law at the close of the evidence and
 after the jury verdict,” Warner-Jenkinson, 
520 U.S. at 39
 n.8. Accordingly, we have consistently rejected doctrine of
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC           23



 equivalents theories as a matter of law when a patentee’s
 case lacks particularized testimony and linking argument.
 See, e.g., VLSI, 87 F.4th at 1344–45 (reversing jury
 verdict); Tex. Instruments, 90 F.3d at 1567–68 (affirming
 grant of judgment as a matter of law); Lear Siegler, 
873 F.2d at 1423
, 1425–27 (reversing jury verdict); Malta, 
952 F.2d at 1321, 1327
 (affirming grant of judgment as a
 matter of law); AquaTex, 
479 F.3d at 1323
 (“[W]e affirm the
 grant of summary judgment because [patentee] did not
 satisfy its burden to present particularized evidence of
 equivalents in opposition to the motion for summary
 judgment.”); Gemalto S.A. v. HTC Corp., 
754 F.3d 1364
,
 1374–75 (Fed. Cir. 2014) (affirming grant of summary
 judgment).
                               3.
      With these principles in mind, we turn to the evidence
 that NexStep adduced to support a finding of infringement
 under the doctrine of equivalents. NexStep points us to the
 following testimony from Dr. Selker, who relied on the
 function-way-result test to attempt to prove that the
 “single action” limitation is met under the doctrine of
 equivalents:
     Q. In terms of the elements of the ’009 patent, can
     you explain why the – I understand that you
     believe that a single action is met literally, but can
     you explain why at the very least the single action
     element is met by the doctrine of equivalents? And
     the –
     A. When you – when you go to debug your – to
     diagnose your device, you’re going through a single
     action. It might be that there’s several button
     presses along the way, but I say that’s the same
     function. And that it’s going to have the same
     purpose which is what I was talking about, I hope.
     I don’t know if I’m –
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 24      NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




      Q. No, you’re doing fine, Doctor. Keep going.
      A. I was confused by that.
      Q. It’s the same function – I’ll just help you out
      here. So it has the same function and it’s a legal
      doctrine and so we have to go through it. Okay?
      Can you explain to the jury why it’s done in
      substantially the same way?
      A. Well, it’s done in the same way in that the stuff
      is all kept up in the cloud for the purpose of doing
      this and it’s going to go and diagnose it using the
      home gateway and it’s going to solve my problem
      without me having to go through and put in my
      model numbers and all of that stuff. So it’s really
      literally using – using this Concierge as more of a
      – somebody to give authorization than to do the
      actual function. I’m not down there in the machine
      room, you know, putting instructions into a
      computer to make it do each of these things.
      Q. And can you explain why the single action
      achieves substantially the same result?
      A. Yeah, the result is that this thing is going to be
      restarted, refreshed, whatever is going to have to
      happen with it without me having to tangle with
      understanding all of the issues of being an IT
      professional or whatever it takes to get this thing
      up. And so it’s going to come with a result of my
      modem working, you know.
 J.A. 445 at 383:25–385:9. This is the only testimony that
 we are aware of in which NexStep asserted infringement
 specifically under the doctrine of equivalents.
     NexStep “had to prove—with particularized testimony
 and linking argument—that the elements of the [accused]
 arrangement were substantially the same as the elements
 of the claimed arrangement.” VLSI, 87 F.4th at 1344–45.
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC       25



 Though “infringement under the doctrine requires ‘only’
 substantial identity, substantial identity must be proven
 with regard to all three elements of the” function-way-
 result test. Lear Siegler, 
873 F.2d at 1425
. Meeting this
 evidentiary burden “at least requires the evidence to
 establish what the function, way, and result of both the
 claimed device and the accused device are, and why those
 functions, ways, and results are substantially the same.”
 Malta, 
952 F.2d at 1327
 n.5. NexStep failed to meet its
 evidentiary burden for several reasons.
     First, Dr. Selker’s testimony never identified a
 particular element or elements in the My Account App as
 being equivalent to the “single action” limitation. Because
 the test is to determine whether “the elements of the
 [accused] arrangement [are] substantially the same as the
 elements of the claimed arrangement,” a patentee must
 identify what element or elements in the accused device are
 equivalent to the claimed limitation. VLSI, 87 F.4th at
 1344–45; see also Malta, 
952 F.2d at 1327
 n.5 (Our
 precedent “at least requires the evidence to establish what
 the function, way, and result of both the claimed device and
 the accused device are.”).         Dr. Selker’s generalized
 reference to “several button presses” fails to identify what
 specific elements in the My Account App are allegedly
 equivalent to the clamed “single action” limitation. This
 lack of specificity is particularly problematic because
 Dr. Selker identified three separate literal infringement
 theories (XfinityAssistant, Troubleshooting Card, and
 Diagnostic Check), each with its own distinct series of
 button presses. Yet Dr. Selker’s passing reference to
 “several button presses” did not guide the jury to focus on
 what theory or what button presses are allegedly
 equivalent. In short, Dr. Selker’s testimony simply does
 not include a particularized identification of what elements
 in the accused device are equivalent to the claimed
 limitation.
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 26     NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




     By itself, the failure to explicitly identify the alleged
 equivalent is fatal to NexStep’s doctrine of equivalents
 theory. If a jury is not told what components are
 equivalent, it necessarily cannot find those components to
 be equivalent to a claim limitation. But Dr. Selker’s
 testimony was also deficient because it failed to provide a
 “meaningful explanation of why” the element or elements
 from the accused product or process are equivalent to the
 claimed limitation for each part of the function-way-result
 test. VLSI, 
87 F.4th at 1344
 (emphasis added).
      As the district court recognized and as is apparent from
 the claim language, the function of the “single action”
 limitation is to cause the home gateway to perform the four
 troubleshooting steps. JMOL Decision, 
2022 WL 1503922
,
 at *6. Indeed, the parties agree that the whole point of the
 claimed invention is to save a user the time and the hassle
 of contacting and communicating with customer service by
 initiating a support session through a single action, such
 as the click of a button. Based on Dr. Selker’s testimony
 above, it is not clear if he identified a function, and to the
 extent he identified the function as “to diagnose your
 device,” it is not clear that this function aligns with the
 claimed function of the “single action” limitation. J.A. 445
 at 384:5–10.       Putting aside these potential errors,
 Dr. Selker testified that “several button presses along the
 way” provides the same function because he “say[s] that’s
 the same function.” 
Id.
     We agree with the district court that this conclusory
 and circular “because I said so” testimony is insufficient.
 Dr. Selker failed to provide what our precedent requires:
 “particularized       testimony   explaining    why      the
 function . . . [was] the same.” Tex. Instruments, 
90 F.3d at 1568
 (citation omitted).        An expert’s “offhand and
 conclusory statements” that the purported equivalent
 “function[s] like” the claim limitation is insufficient.
 Malta, 
952 F.2d at 1327
. NexStep therefore failed to
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC            27



 provide a sufficient evidentiary showing under the function
 prong of the function-way-result test.
     As for the way prong, Dr. Selker’s testimony is difficult
 to parse:
     Well, it’s done in the same way in that the stuff is
     all kept up in the cloud for the purpose of doing this
     and it’s going to go and diagnose it using the home
     gateway and it’s going to solve my problem without
     me having to go through and put in my model
     numbers and all of that stuff. So it’s really literally
     using – using this Concierge as more of a –
     somebody to give authorization than to do the
     actual function. I’m not down there in the machine
     room, you know, putting instructions into a
     computer to make it do each of these things.
 J.A. 445 at 384:17–385:1.      The district court aptly
 described this testimony as “word salad” and noted that, to
 the extent it communicated anything to the jury, this
 testimony “did not provide particularized testimony or a
 linking argument for why several button presses perform
 the claimed method in the same way as the claimed single
 action.” JMOL Decision, 
2022 WL 1503922
, at *7.
      We agree with the district court that this testimony is
 insufficient because of its “failure to articulate how [the]
 accused process operates in substantially the same way.”
 Akzo Nobel Coatings, Inc. v. Dow Chem. Co., 
811 F.3d 1334, 1343
 (Fed. Cir. 2016). Once again, it is not clear that
 Dr. Selker identified the “way” that the accused product or
 the claim limitation operates. To the extent that he
 adequately identified the way for either, he fails to explain
 how the “several button presses” for any of the three My
 Account App tools (which the jury necessarily found to be
 multiple actions as opposed to a single action) should be
 understood to be performing the single action limitation in
 substantially the same way. In other words, Dr. Selker
 failed to provide “meaningful explanation of why” the
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 28      NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 “several button presses” operate in substantially the same
 way as the “single action” limitation. VLSI, 
87 F.4th at 1344
.
      Finally, for the result prong, Dr. Selker testified that:
       [T]he result is that this thing is going to be
      restarted, refreshed, whatever is going to have to
      happen with it without me having to tangle with
      understanding all of the issues of being an IT
      professional or whatever it takes to get this thing
      up. And so it’s going to come with a result of my
      modem working, you know.
 J.A. 445 at 385:4–9. The district court determined that
 this testimony was “untethered from the claim language”
 and “amounts to little more than ‘generalized testimony as
 to the overall similarity between the claims and the
 accused infringer’s product.’” JMOL Decision, 
2022 WL 1503922
, at *7 (quoting Tex. Instruments, 
90 F.3d at 1567
).
 We agree with the district court on both points.
     The claim language provides that the result of the
 “single action” limitation is the home gateway performs the
 four troubleshooting steps.        Here, Dr. Selker merely
 testified that something is going to happen so that the
 modem works. That result is not in accord with the specific
 result required by the claim language.
      While our precedent doesn’t necessarily require an
 expert’s testimony to be an ipsis verbis recitation of the
 claim, Dr. Selker’s identified result is also too generalized,
 unclear, and unconnected to the claimed invention.
 Though the result of the claimed invention as a whole is to
 initiate a support session, “[g]eneralized testimony as to
 the overall similarity between the claims and the accused
 infringer’s product or process [does] not suffice.” Tex.
 Instruments, 
90 F.3d at 1567
.
     Overall, Dr. Selker’s testimony is similar to the
 testimony we found inadequate in Texas Instruments. In
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC        29



 that case, one of the patentee’s experts provided only
 “generalized testimony as to [the] overall similarity” of the
 claimed and accused processes. 90 F.3d at 1567–68. The
 patentee’s other expert witness merely “testified, in
 conclusive fashion, that the accused processes . . . met the
 Graver Tank function, way, result test” but did not explain
 “whether or how the way the accused product operates was
 similar to the patent claim,” nor provide “any
 particularized testimony explaining why the function and
 result were the same.” 
Id. at 1568
 (cleaned up). We
 explained that neither witness’s testimony was “sufficient
 to support a finding of infringement under the doctrine of
 equivalents.” 
Id.
 Here, Dr. Selker’s testimony—including
 his failure to identify what particular elements are
 allegedly equivalent; failure to explain why the function,
 way, and result are substantially similar between the
 accused elements and the claim limitation; and resorting
 to comparing the overall similarities of the accused device
 and the claimed invention—fares no better than the
 testimony in Texas Instruments.
     For all these reasons, Dr. Selker’s testimony failed to
 provide the requisite particularized testimony and linking
 argument. NexStep’s infringement theory under the
 doctrine of equivalents was therefore legally insufficient
 because it failed to comply with “the specific evidentiary
 requirements necessary to prove infringement under the
 doctrine” of equivalents. Tex. Instruments, 
90 F.3d at 1566
.
 Accordingly, the district court properly granted, and indeed
 was “obliged to grant,” judgment as a matter of law.
 Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 
520 U.S. 17
, 39 n.8 (1997).
                              D.
    NexStep raises several arguments in favor of
 nonetheless reversing the district court’s order. We address
 each in turn, and none is persuasive.
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 30      NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, 
LLC 1
.
     NexStep argues that it offered a sufficient basis for the
 jury to find infringement under the “insubstantial
 differences” formulation of the doctrine of equivalents. We
 disagree.
     For starters, NexStep did not present an independent
 “insubstantial differences” theory at trial. Dr. Selker
 phrased his opinion and substantive analysis under the
 function-way-result test. See J.A. 445 at 383:25–385:15.
 He also agreed that his opinion was that “the single action
 limitation is satisfied under the doctrine of equivalents
 because it performs substantially the same function in
 substantially the same way to achieve substantially the
 same result.”      
Id.
 at 385:10–15.      And the phrase
 “insubstantial differences” (or any similar phrase) does not
 appear in Dr. Selker’s testimony. These facts support a
 conclusion that Dr. Selker did not provide an insubstantial
 differences theory that was not dependent on his function-
 way-result theory.
     In any event, the testimony adduced at trial confirms
 that Dr. Selker in fact did not provide sufficient evidence
 to show (separately from his function-way-result
 presentation or, indeed, at all) that certain elements of the
 accused devices are insubstantially different from the
 single action limitation. NexStep points us to the following
 direct examination testimony to support its argument that
 Dr. Selker testified that a sequence of screen taps is
 insubstantially different from the “single action”
 limitation:
      Q. In your view, does the – tell us in your view,
      what is – does a single action, can it initiate a
      troubleshooting process?
      A. Yes.
      Q. Can you explain why?
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC            31



     A. Well, a single action like fixing your modem is
     something that you embark to do and, you know,
     whatever a single action is, let’s say it’s even
     pressing a button, you have to see the button, you
     have to go think about it, you have to move your
     finger to it, you have to go and press it and you have
     to see that it’s responded. So whatever a single
     action is, whether a single press or other things,
     there’s some parts to it. And I call those steps a
     single action.
 J.A. 434 at 341:25–342:18 (objection omitted). NexStep
 also identified the following testimony from Dr. Selker’s
 cross examination:
     Q. When you gave your equivalents opinion, you
     said that your opinion is that the words “single
     action” are substantially the same as multiple
     single actions; correct?
     A. No, not – not all single actions. They’re –
     multiple steps might be contained in a single
     action. For example, when you throw a baseball,
     you pick it up, you orient it, you get it in your palm,
     you throw it. There’s several steps to making a
     baseball, to throwing a baseball.
                              ***
     Q. Well, let’s look a little bit further down [in your
     expert report] to see if this was, in fact, a typo.
     Next sentence, to the extent the action to start the
     troubleshooting processing is not literally a single
     action, it is at least equivalent to a single action
     because a single stream-like action starts the
     process to begin troubleshooting including
     collecting buffer data from customer service such
     as identification data. Do you see that?
     A. So this is in my data –
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 32       NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




      Q. Dr. Selker –
      A. I’ll just trying to explain it.
      Q. I understand. And Mr. Hannah will have – he’ll
      be able to give you a chance to frame it. My first
      question is just, do you see it?
      A. I see it.
 J.A. 460 at 444:22–445:4, 446:6–20.
     In essence, NexStep has identified direct examination
 testimony opining that several steps can be a single action
 and cross examination testimony opining that multiple
 steps may be contained in a single action and that
 Dr. Selker sees in his report that a single stream-like
 action is at least equivalent to a “single action.”6
      As an initial matter, this testimony does not provide an
 insubstantial differences theory that makes up for the
 deficiency of the function-way-result evidence. The first
 two points identified above are literal infringement
 testimony: Dr. Selker believes that a single action can
 literally be satisfied by several steps. The third point, at
 best, states that Dr. Selker has provided a doctrine of
 equivalents theory, but nothing suggests that he took an
 “insubstantial differences” route independent of his
 function-way-result line of reasoning.
    But even if we consider the merits of NexStep’s
 argument, this testimony still fails to provide



      6  To the extent NexStep relies on counsel’s questions,
 “[s]tatements of counsel . . . are not evidence.” Galen Med.
 Assocs., Inc. v. United States, 
369 F.3d 1324, 1339
 (Fed. Cir.
 2004). And it is black letter law that counsel’s unsworn fact
 statements are not evidence and therefore cannot sustain
 an infringement finding. Gemtron Corp. v. Saint-Gobain
 Corp., 
572 F.3d 1371, 1380
 (Fed. Cir. 2009).
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC        33



 particularized testimony and linking argument. Under an
 “insubstantial differences” formulation, “a patentee must
 still provide particularized testimony and linking
 argument as to the ‘insubstantiality of the differences’
 between the claimed invention and the accused device or
 process” to show infringement under the doctrine of
 equivalents. Tex. Instruments, 
90 F.3d at 1567
. Similar to
 his testimony under the function-way-result test,
 Dr. Selker’s testimony neither particularly identified what
 specific elements of the accused products are allegedly
 equivalent to the “single action” limitation nor offered the
 required testimony explaining why those elements were
 only insubstantially different in light of the claim language
 reciting what is being avoided by the “single action.” To
 put it simply, Dr. Selker never stated or explained why
 several button presses are insubstantially different from a
 single action, particularly given that the point of the
 “single action” limitation was that a single action saved the
 user from undertaking the multiple steps typically
 required to initiate a customer support session. Either of
 these shortcomings is sufficient to foreclose a verdict of
 infringement under the doctrine of equivalents.
                              2.
      NexStep also argues that we should reverse the district
 court because NexStep’s literal infringement testimony
 coupled with its doctrine of equivalents testimony provides
 an adequate basis for finding infringement under the
 doctrine of equivalents. NexStep contends that the district
 court failed to consider Dr. Selker’s literal infringement
 testimony, rendering its conclusion to grant judgment as a
 matter of law erroneous. This argument is unpersuasive
 for two reasons.
     First, the premise of this argument is incorrect. The
 district court expressly considered Dr. Selker’s literal
 infringement testimony in rendering its decision to grant
 judgment as a matter of law. After articulating the law,
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 34     NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 the district court noted that “Dr. Selker’s literal
 infringement testimony can support NexStep’s DOE
 contentions.” JMOL Decision, 
2022 WL 1503922
, at *5.
 Indeed, the district court found that “Dr. Selker’s literal
 infringement testimony somewhat cures the vagueness of
 his DOE claim limitation testimony.” 
Id.
 But the district
 court concluded that “NexStep has simply not met its
 burden.” 
Id.
 Thus, it is not true that the district court
 failed to consider Dr. Selker’s literal infringement
 testimony.
      Second, this argument also fails on the merits. Though
 “[o]ur ‘particularized testimony’ standard does not require
 [an expert witness] to re-start his testimony at square one
 when transitioning to a doctrine of equivalents analysis,”
 Paice LLC v. Toyota Motor Corp., 
504 F.3d 1293, 1305
 (Fed.
 Cir. 2007), “[t]he evidence and argument on the doctrine of
 equivalents cannot merely be subsumed in plaintiff’s case
 of literal infringement,” Lear Siegler, 
873 F.2d at 1425
.
 That is, even if there “was evidence and argument on literal
 infringement[] that may also bear on equivalence,” that
 “does not satisfy” the requirements of the doctrine of
 equivalents in the absence of particularized testimony and
 linking argument. Lear Siegler, 
873 F.2d at 1425
.
     Here, even incorporating the literal infringement
 testimony, NexStep fell short of providing particularized
 testimony and linking argument. As already discussed,
 NexStep failed to produce “evidence to establish what the
 function, way, and result of both the claimed device and the
 accused device are, and why those functions, ways, and
 results are substantially the same.” Malta, 
952 F.2d at 1327
 n.5; see supra Section III.C. Even if we assume, as
 the district court did, that the literal infringement
 testimony allowed the jury to understand what “several
 button presses” Dr. Selker alleged to be equivalent and if
 we assume that the literal infringement testimony
 provided the function, way, and result of the “single action”
 limitation, Dr. Selker failed to explain why the function,
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC      35



 way, and result of the accused elements and the claimed
 limitation are substantially the same.          In short,
 Dr. Selker’s conclusory testimony is on par with other
 testimony we have rejected as inadequate. See, e.g., VLSI,
 87 F.4th at 1343–45; Tex. Instruments, 90 F.3d at 1567–68;
 Lear Siegler, 873 F.2d at 1425–26.
                             3.
     NexStep’s final argument is that we should adopt a
 novel exception to the requirement of particularized
 testimony and linking argument. According to NexStep,
 for certain “easily understandable” technologies, a
 patentee simply need not offer particularized testimony
 and linking argument from a skilled artisan. We reject this
 argument because it is contrary to both our precedent and
 the policies underlying why we require particularized
 testimony and linking argument.
     NexStep’s ask for an “easily understandable”
 technology exception is particularly unpersuasive because
 the cases in which we explicated the particularized
 testimony and linking argument requirement dealt with
 “easily understandable” technologies. In 1989, we first
 coined the phrase “particularized testimony and linking
 argument” in the seminal case of Lear Siegler, noting that
 “the three Graver Tank [function-way-result] elements
 must be presented in the form of particularized testimony
 and linking argument.” Lear Siegler, 
873 F.2d at 1426
.
 Two years later, we explained that our precedent “at least
 requires the evidence to establish what the function, way,
 and result of both the claimed device and the accused
 device are, and why those functions, ways, and results are
 substantially the same.” Malta, 
952 F.2d at 1327
 n.5. Lear
 Siegler and Malta respectively dealt with inventions for
 box springs used with a mattress and handbells used in
 churches and schools. Yet we still required particularized
 testimony and linking argument to prove infringement
 under the doctrine of equivalents.       That this court
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 36     NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 explicated  the    particularized-testimony-and-linking-
 argument requirement in cases dealing with “easily
 understandable” technologies cuts sharply against now
 making an exception that would apply to those very same
 cases.
     Indeed, more than 30 years later, we have stayed the
 course. In VLSI, the jury was confronted with the “not-so
 easily understandable” technology of managing the
 memory-operating-voltage and clock speed in electronic
 devices. Consistent with our precedent, the patentee was
 required to provide “particularized testimony and linking
 argument as to the insubstantiality of the differences
 between the claimed invention and the accused device.”
 VLSI, 
87 F.4th at 1343
 (collecting cases). Thus, from
 handbells to complex electronics, particularized testimony
 and linking argument is always required.
     In fact, we have never recognized a technology-specific
 exception to the evidentiary rules governing the doctrine of
 equivalents.      Simply put, our precedent requires
 particularized testimony and linking argument, regardless
 of the complexity or the simplicity of the underlying
 technology. See, e.g., VLSI, 87 F.4th at 1336–39, 1342–45
 (patents for adjusting operating voltage and clock speed in
 electronic devices); Akzo Nobel Coatings, Inc. v. Dow Chem.
 Co., 
811 F.3d 1334
, 1336–37, 1342–43 (Fed. Cir. 2016)
 (patent “directed to an extrusion process that generates
 low viscosity aqueous polymer dispersions”); Gemalto S.A.
 v. HTC Corp., 
754 F.3d 1364, 1366, 1374
 (Fed. Cir. 2014)
 (“The asserted claims are directed to applications that are
 converted from a high level programming language into
 another format that is suitable for resource-constrained
 computing devices.”); AquaTex Indus., Inc. v. Techniche
 Sols., 
479 F.3d 1320, 1323
, 1328–29 (Fed. Cir. 2007) (“The
 ’977 patent claims a method for cooling a person through
 evaporation by use of a multi-layered, liquid-retaining
 composite material in evaporative cooling garments.”);
 Paice, 504 F.3d at 1296–1301, 1304–06 (“The three patents
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC           37



 at issue in this case relate to drive trains for hybrid electric
 vehicles.”); Tex. Instruments, 
90 F.3d at 1560
, 1566–67
 (“These patents claim different aspects of a process for
 encapsulating electronic components in plastic.”); Malta,
 952 F.2d at 1321–22, 1327 (“The patent in suit . . . is
 directed to improvements in the design of handbells, of the
 type used by music groups in churches, schools, and the
 like.”); Lear Siegler, 873 F.2d at 1423–26 (springs used in a
 mattress’s box spring assembly); see also Malta., 
952 F.2d at 1330
 (Michel, J., concurring) (“The simplicity of the
 [claimed invention], so emphasized by the dissent, is not
 relevant either. . . . [T]he rule of Lear Siegler is a
 prophylactic rule of general applicability. As such, it must
 cover the whole range of infringement cases, many of which
 do indeed involve complex technology.”); 
id. at 1334
 (Newman, J., dissenting) (“[T]hese                [evidentiary]
 requirements must be fulfilled no matter how simple the
 invention.”).7
     It makes sense that the patentee must provide
 particularized testimony and linking argument in every



     7    NexStep cites only WCM Industries, Inc. v. IPS
 Corporation, 
721 F. App’x 959
 (Fed. Cir. 2018), to support
 its argument. That case is non-precedential. It is also
 inapposite. In that case, we reversed the district court’s
 grant of judgment as a matter of law because the patentee
 “provided sufficient” evidence under the doctrine of
 equivalents. 
Id. at 969
. Along the way, we reaffirmed that
 “the difficulties and complexities of the doctrine[] must be
 presented to the jury or other fact-finder through the
 particularized testimony of a person of ordinary skill in the
 art.” 
Id. at 966
 (internal quotation marks omitted)
 (quoting AquaTex, 
479 F.3d at 1329
). Thus, we merely
 found, on the facts of that case, the patentee had presented
 particularized testimony and linking argument sufficient
 to support the jury’s verdict.
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 38     NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 case because “the difficulties and complexities of the
 doctrine require” it. AquaTex, 
479 F.3d at 1329
 (emphasis
 added); see also Tex. Instruments, 90 F.3d at 1566–67 (“Our
 court set forth these evidentiary requirements in those
 earlier cases because, although the standard for
 infringement under the doctrine of equivalents is simple to
 articulate, it is conceptually difficult to apply.”). The
 difficulties and complexities of the doctrine are present
 regardless of the simplicity of the underlying technology.
 Even if a jury understands the underlying technology, the
 doctrine of equivalents itself introduces a distinct and
 complex inquiry that requires appropriate guidance. See
 AquaTex, 
479 F.3d at 1329
; Tex. Instruments, 90 F.3d at
 1566–67.
     Accordingly, regardless of the technology at issue,
 patentees must still present juries with particularized
 testimony and linking argument to ensure that the jury
 does not misapply the doctrine and thereby stray beyond
 the doctrine’s “properly limited” role. VLSI, 
87 F.4th at 1342
 (citing Warner-Jenkinson, 
520 U.S. at 35, 39
). An
 example of a misapplication of the doctrine is if the
 factfinder relies on “merely generalized testimony as to
 overall similarity.” Tex. Instruments, 
90 F.3d at 1568
. By
 guiding the jury’s attention to particularized testimony and
 linking argument that compares the accused elements to
 the claimed limitation at issue, we avoid inviting the jury
 to resort to improper generalized comparisons between the
 overall claimed invention and the accused product. This
 requirement therefore “ensure[s] that a jury is provided
 with the proper evidentiary foundation from which it may
 permissibly conclude that a claim limitation has been met
 by an equivalent.” Comark Commc’ns, Inc. v. Harris Corp.,
 
156 F.3d 1182, 1188
 (Fed. Cir. 1998).
     In summary, NexStep has provided no persuasive
 reason to break with decades of our precedent, which has
 been explicit and consistent in requiring particularized
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC           39



 testimony and linking argument regardless of the
 complexity or simplicity of the underlying technology.
                               IV.
     We briefly address two points that are central to the
 dissent’s disagreement with the majority opinion.
     First, the dissent states that “[t]he majority concocts a
 rigid new rule that in all cases a patentee must present
 expert opinion testimony to prove infringement under the
 doctrine of equivalents,” and “disagree[s] with the
 majority’s extrapolation that expert testimony is always
 required.” Dissenting Op. 7. That is not correct, for our
 discussion of the use of expert testimony in proving
 infringement under the doctrine of equivalents is limited
 to quoting the standard articulated in AquaTex Industries,
 Inc. v. Techniche Solutions: “[B]oth the Supreme Court and
 this court have made clear that the evidence of equivalents
 must be from the perspective of someone skilled in the art,
 for example through testimony of experts or others versed
 in the technology; by documents, including texts and
 treatises; and, of course, by the disclosures of the prior art.”
 
479 F.3d at 1329
 (cleaned up); see 
id.
 (“[W]hen the patent
 holder relies on the doctrine of equivalents,” we “require
 that evidence be presented to the jury or other fact-finder
 through the particularized testimony of a person of
 ordinary skill in the art, typically a qualified expert.”); see
 also Maj. Op. 20.
     Second, according to the dissent, “not only did
 Dr. Selker testify that several button presses are the same
 as a single action in the context of the doctrine of
 equivalents, but Dr. Selker also testified on the same point
 in the context of literal infringement.” Dissenting Op. 5.
 But testifying that several button presses are the same as
 a single action is not the correct test.           To prove
 infringement under the doctrine of equivalents (at least
 when a party, like NexStep, is relying on the function-way-
 result framework), there must be particularized testimony
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 40       NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 explaining why “the accused product performs
 ‘substantially the same function in substantially the same
 way to obtain the same result’”—not testimony that the
 accused product is the same as (or meets) the claim
 limitation. Mylan Institutional LLC v. Aurobindo Pharma
 Ltd., 
857 F.3d 858, 866
 (Fed. Cir. 2017) (quoting Graver
 Tank, 
339 U.S. at 608
). By finding no literal infringement,
 the jury rejected NexStep’s position that “several button
 presses” are the same as a single action, and instead
 necessarily concluded that several button presses by a user
 are multiple actions. For NexStep’s back-up infringement
 theory under the doctrine of equivalents, then, NexStep
 had to pivot and explain, in the alternative, why those
 several button presses—if found to entail multiple
 actions—nevertheless perform substantially the same
 function in substantially the same way to obtain the same
 result as the claimed “single action.” But NexStep never
 provided that why.
                              V.
       Based on how we resolve the infringement issues in
 this case, we need not address NexStep’s damages
 argument or Comcast’s conditional cross appeal.8 We have
 considered the parties’ remaining arguments and find


      8  Comcast’s express making of its cross-appeal
 conditional means that we need not address validity if we
 affirm non-infringement and therefore may dismiss the
 cross-appeal. We also note that Comcast exclusively
 asserted invalidity under § 101 as a defense to liability; it
 did not assert a counterclaim for a declaratory judgment of
 invalidity. See NexStep, Inc. v. Comcast Cable Commc’ns,
 LLC, No. 19-cv-1031, ECF No. 40 at 32 (D. Del. Dec. 17,
 2019); see also Cardinal Chem. Co. v. Morton Int’l, Inc., 
508 U.S. 83
, 93–94 (1993) (distinguishing between mootness of
 invalidity defense and mootness of declaratory judgment
 claim asserting invalidity).
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC    41



 them unpersuasive. For the foregoing reasons, we affirm
 the district court’s final judgment with respect to non-
 infringement of the ’009 and ’802 patents, and we dismiss
 Comcast’s cross-appeal.
  AFFIRMED AS TO THE APPEAL AND DISMISSED
          AS TO THE CROSS-APPEAL
                          COSTS
 Costs to Comcast.
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    United States Court of Appeals
        for the Federal Circuit
                    ______________________

                      NEXSTEP, INC.,
                      Plaintiff-Appellant

                              v.

     COMCAST CABLE COMMUNICATIONS, LLC,
            Defendant-Cross-Appellant
              ______________________

                2022-1815, 2022-2005, 2022-2113
                    ______________________

     Appeals from the United States District Court for the
 District of Delaware in No. 1:19-cv-01031-RGA, Judge
 Richard G. Andrews.
                 ______________________

 REYNA, Circuit Judge, concurring-in-part and dissenting-
 in-part.
     I am pleased to concur in part with the majority
 opinion. I dissent only to that portion of the majority
 opinion that affirms the district court’s entry of judgment
 as a matter of law of non-infringement of the ’009 patent.
 I dissent for two reasons. First, I believe the jury’s verdict
 that Comcast infringed the ’009 patent under the doctrine
 of equivalents is supported by substantial evidence.
 Second, I believe the majority’s new rule that patentees
 must always present expert opinion testimony to prove
 infringement under the doctrine of equivalents is incorrect
 and contrary to existing precedent. Thus, I would reverse
 the district court’s decision that disturbed the jury verdict.
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 2      NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




      The majority is correct that in determining whether to
 overturn a jury verdict, the correct law in this case is that
 of the Third Circuit. The Third Circuit respects jury
 verdicts. Accordingly, “entry of judgment as a matter of law
 is a ‘sparingly’ invoked remedy.” Marra v. Phila. Hous.
 Auth., 
497 F.3d 286, 300
 (3d Cir. 2007), as amended
 (Aug. 28, 2007) (citation omitted). It is only in “rare cases”
 that, “following a jury verdict, judgment as a matter of law
 [is] warranted.” Fair Hous. Council v. Main Line Times,
 
141 F.3d 439, 442
 (3d Cir. 1998); see also Pitts v. Delaware,
 
646 F.3d 151, 152
 (3d Cir. 2011). A “court may grant a
 judgment as a matter of law contrary to the verdict only if
 ‘the record is critically deficient of the minimum quantum
 of evidence’ to sustain the verdict.” Acumed LLC v.
 Advanced Surgical Servs., Inc., 
561 F.3d 199, 211
 (3d Cir.
 2009) (citation omitted). When a jury has heard extensive
 testimony, judgment as a matter of law is “only . . .
 appropriate in the extraordinary circumstance that none of
 that evidence could lead a reasonable jury to [reach its
 conclusion].” Avaya Inc., RP v. Telecom Labs, Inc., 
838 F.3d 354, 373
 (3d Cir. 2016) (emphasis added).
     We must “view[] the evidence in the light most
 favorable to the nonmovant and giv[e] it the advantage of
 every fair and reasonable inference.” Lightning Lube, Inc.
 v. Witco Corp., 
4 F.3d 1153, 1166
 (3d Cir. 1993) (citation
 omitted). The party seeking judgment as a matter of law
 “must show that the jury’s findings, presumed or express,
 are not supported by substantial evidence.” Interactive
 Pictures Corp. v. Infinite Pictures, Inc., 
274 F.3d 1371, 1376
 (Fed. Cir. 2001) (citation omitted); see also Lightning Lube,
 
4 F.3d at 1184
. Substantial evidence is “such relevant
 evidence as a reasonable mind might accept as adequate to
 support a conclusion.” Consol. Edison Co. v. NLRB, 
305 U.S. 197, 229
 (1938). Thus, “the court must determine
 whether a reasonable jury could have found for the
 prevailing party.” Starceski v. Westinghouse Elec. Corp., 
54 F.3d 1089, 1095
 (3d Cir. 1995) (citation omitted). It is
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC         3



 against this backdrop that we must analyze whether
 substantial evidence supports the jury’s verdict.
     A non-technical non-complex factual issue was put to
 the jury: whether the process of several button presses is
 equivalent to a “single action,” a single press. The jury
 heard evidence from both parties, received instructions
 from the court, and then answered in the affirmative. Yet,
 the majority overrides this finding based on its belief that
 NexStep failed to provide “particularized testimony and
 linking argument as to the insubstantiality of the
 differences between the claimed invention and the accused
 device.” Maj. Op. 21 (quoting VLSI Tech. LLC v. Intel
 Corp., 
87 F.4th 1332, 1343
 (Fed. Cir. 2023)).
     In my view, the majority commits two errors. First, the
 majority analyzes NexStep’s evidence of infringement
 under the doctrine of equivalents in a vacuum and fails to
 adhere to the substantial evidence standard of review.
 Second, the majority’s reasoning imposes a new rule that a
 patentee must present expert opinion testimony to prove
 infringement under the doctrine of equivalents.
                               I
     The majority disregards the totality of the evidence
 presented and instead analyzes NexStep’s evidence of
 infringement under the doctrine of equivalents in a
 vacuum. The majority unduly focuses on testimony from
 NexStep’s expert, Dr. Selker, on the function-way-result
 test of the doctrine of equivalents. Maj. Op. 22–29. In
 doing so, the majority ignores both the context in which the
 jury heard this testimony and the other evidence the jury
 received that is probative as to the question of equivalence.
 This approach is contrary to our precedent, which does not
 require expert witnesses to “re-start [their] testimony at
 square one when transitioning to a doctrine of equivalents
 analysis.” Paice LLC v. Toyota Motor Corp., 
504 F.3d 1293, 1305
 (Fed. Cir. 2007). This is because juries do not consider
 evidence in categories, but rather, consider the totality of
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 4      NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 the evidence presented. Brooktree Corp. v. Advanced Micro
 Devices, 
977 F.2d 1555, 1573
 (Fed. Cir. 1992).
     Here, NexStep presented its doctrine of equivalents
 evidence in the context of its literal infringement evidence.
 See VLSI, 
87 F.4th at 1343
 (“[Patentee’s] equivalents
 contention is best understood in light of its literal-
 infringement case.”). And we must presume the jury
 considered all of NexStep’s evidence when rendering its
 verdict, rather than only a subset of the evidence. See i4i
 Ltd. P’ship v. Microsoft Corp., 
598 F.3d 831, 849
 (Fed. Cir.
 2010) (“[W]e assume the jury considered all the evidence”
 presented in rendering its verdict.). When viewed through
 that lens, it becomes clear that under Third Circuit law,
 NexStep provided a legally sufficient evidentiary basis for
 a reasonable jury to decide in its favor.
     This is not to say that literal infringement testimony
 alone is sufficient to show infringement under the doctrine
 of equivalents. As we have recognized, “[t]he evidence and
 argument on the doctrine of equivalents cannot merely be
 subsumed in plaintiff ’s case of literal infringement.” Lear
 Siegler, Inc. v. Sealy Mattress Co., 
873 F.2d 1422, 1425
 (Fed. Cir. 1989). But that is not the case here. Rather,
 when literal infringement evidence is coupled with
 evidence of infringement under the doctrine of equivalents,
 the combination of evidence can sufficiently show
 infringement under the doctrine of equivalents. Id.; see
 also Paice, 
504 F.3d at 1305
 (“Indeed, we think it desirable
 for a witness to incorporate earlier testimony in order to
 avoid duplication.”).
     For example, the majority faults Dr. Selker for
 allegedly failing to identify “a particular element or
 elements” that is equivalent to the “single action”
 limitation. Maj. Op. 24. Yet the majority recognizes that
 Dr. Selker identified “several button presses” as the critical
 function. Maj. Op. 25. The majority also acknowledges
 that Dr. Selker “identified three separate literal
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC          5



 infringement theories (XfinityAssistant, Troubleshooting
 Card, and Diagnostic Check), each with its own distinct
 series of button presses” when addressing literal
 infringement. 
Id.
 And Dr. Selker identified the distinct
 “series of button presses” when testifying about literal
 infringement under each of these theories. J.A. 431, 329:4–
 330:16; J.A. 434, 340:11–341:8; J.A. 437, 353:15–354:5. So,
 when Dr. Selker later referred to “several button presses”
 when addressing infringement under the doctrine of
 equivalents, the jury could reasonably conclude that Dr.
 Selker was referring them to specific elements he identified
 during his literal infringement testimony. Paice, 
504 F.3d at 1305
 (“The fact that [patentee’s expert] did not explicitly
 [incorporate his earlier testimony] does not mean he did
 not implicitly [do so].”).
     The majority also faults Dr. Selker for “never stat[ing]
 or explain[ing] why several button presses are
 insubstantially different from a single action.” Maj. Op. 32.
 This is not a shortcoming of Dr. Selker’s testimony, but
 rather, the majority’s interpretation and restrictive review
 of Dr. Selker’s testimony. To be clear, not only did Dr.
 Selker testify that several button presses are the same as
 a single action in the context of the doctrine of equivalents,
 but Dr. Selker also testified on the same point in the
 context of literal infringement. Dr. Selker first testified
 that:
     [E]ven pressing [one] button, you have to see the
     button, you have to go think about it, you have to
     move your finger to it, you have to go and press it
     and you have to see that it’s responded. So
     whatever a single action is, whether a single press
     or other things, there’s some parts to it. And I call
     those steps a single action.
 J.A. 434, 342:12–18. Further, Dr. Selker also testified that
 “multiple steps might be contained in a single action,”
 because, “[f]or example, when you throw a baseball, you
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 6      NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 pick it up, you orient it, you get it in your palm, you throw
 it. There’s several steps to making a baseball, to throwing
 a baseball.” J.A. 460, 445:1–4. Finally, when discussing
 the doctrine of equivalents, Dr. Selker testified that
 “[w]hen you . . . diagnose your device, you’re going through
 a single action. It might be that there’s several button
 presses along the way, but I say that’s the same [as a single
 action].” J.A. 445, 384:5–8. The majority fails to address
 the substance of his opinions on this point.
     In short, Dr. Selker testified that several button
 presses are a single action because single actions have
 multiple steps, such as throwing a baseball. Further, the
 steps a user takes to perform one button press are the same
 regardless of whether more than one press is taken. Yet
 even if several button presses are not literally a single
 action, the two are nonetheless equivalent. Having heard
 this evidence and argument, the jury should be permitted
 to reject Dr. Selker’s first opinion but accept his second
 opinion, which is inherently based on his first opinion.
     The majority’s remaining criticisms of Dr. Selker’s
 testimony are similarly unjustified and unsupported by the
 record. For example, the majority believes that “it is not
 clear that Dr. Selker identified the ‘way’ that the accused
 product or the claim limitation operates.” Maj. Op. 27. But
 the record is not “critically deficient of the minimum
 quantum of evidence” on this point. See Acumed LLC, 
561 F.3d at 211
; J.A. 428–29, 318:19–322:8 (Dr. Selker
 demonstrating the functionality of Comcast’s product);
 J.A. 434–36, 340:11–349:13 (Dr. Selker explaining how
 Comcast’s product and the “single action” claim limitation
 operate); J.A. 431, 329:4–330:16 (Dr. Selker explaining
 several different ways Comcast’s product starts the
 claimed “support session”); J.A. 437, 353:15–354:5 (Dr.
 Selker explaining how several different single button clicks
 within Comcast’s product start a “system check”).
 Similarly, the majority asserts that “Dr. Selker merely
 testified that something is going to happen so that the
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC        7



 modem works.” Maj. Op. 28. The record indicates
 otherwise. As a result, this is not “the extraordinary
 circumstance that none of that evidence could lead a
 reasonable jury to [reach its conclusion].” See Avaya Inc.,
 RP, 
838 F.3d at 373
; J.A. 434–35, 342:19–343:8 (Dr. Selker
 explaining how Comcast’s product performs the claimed
 communication “with a home gateway” via the cloud);
 J.A. 435–36, 345:5–349:13 (Dr. Selker explaining Comcast
 technical documents that show how the claimed
 “responsive to a single action” limitation causes the
 subsequent claim limitations to occur in Comcast’s
 product).
     A motion for judgment as a matter of law is a “narrow
 inquiry.” Marra, 
497 F.3d at 300
. That narrow inquiry
 must end “when there is shown to be substantial evidence,
 on the record as a whole, as could have been accepted by a
 reasonable jury as probative of the issue.” Nat’l Presto
 Indus., Inc. v. W. Bend Co., 
76 F.3d 1185, 1192
 (Fed.
 Cir. 1996) (citation omitted). As illustrated above, Dr.
 Selker’s testimony is substantial evidence on which a
 reasonable jury could find for NexStep. Thus, the inquiry
 should end. But there is more.
                              II
     The majority concocts a rigid new rule that in all cases
 a patentee must present expert opinion testimony to prove
 infringement under the doctrine of equivalents. The
 majority’s new rule is superficial because it fails to
 recognize that each individual patent infringement case
 presents unique facts and circumstances. There is no
 cookie-cutter approach to patent infringement.
     I agree with the majority’s observation that “our
 precedent at least requires the evidence to establish what
 the function, way, and result of both the claimed device and
 the accused device are, and why those functions, ways, and
 results are substantially the same.” Maj. Op. 35 (internal
 quotation marks and some emphasis omitted) (quoting
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 8       NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 Malta v. Schulmerich Carillons, Inc., 
952 F.2d 1320
,
 1327 n.5 (Fed. Cir. 1991)); see also Lear Siegler, 
873 F.2d at 1425
. But I disagree with the majority’s extrapolation that
 expert testimony is always required. Indeed, our precedent
 establishes that “testimony of experts” is an “example” of
 the type of evidence that can be employed in a doctrine of
 equivalents analysis. AquaTex Indus., Inc. v. Techniche
 Sols., 
479 F.3d 1320, 1329
 (Fed. Cir. 2007) (“[E]vidence of
 equivalents must be from the perspective of someone
 skilled in the art, for example through testimony of experts
 or others versed in the technology; by documents, including
 texts and treatises; and, of course, by the disclosures of the
 prior art.” (emphasis added) (citation and internal
 quotation marks omitted)).
     There is also no doubt that in complex cases, expert
 testimony must be offered. See VLSI, 87 F.4th at 1335–39
 (describing memory-operating-voltage and clock speed of
 electronic devices). But the same is not true where the
 technology or the specific doctrine of equivalents issue is so
 simple that evidence other than expert testimony is more
 than adequate for a jury to understand the issues and find
 equivalence.1 That is the case here. While I would find Dr.
 Selker’s testimony is sufficient to support the jury’s verdict,
 I would also find that the jury did not need expert
 testimony to answer the technologically-simple question
 presented here of whether several button presses are
 equivalent to a “single action.”



     1   Such an approach would also be consistent with our
 law on expert testimony for nonobviousness.              See
 Intercontinental Great Brands LLC v. Kellogg N. Am. Co.,
 
869 F.3d 1336, 1348
 (Fed. Cir. 2017) (“[S]ome cases involve
 technologies and prior art that are simple enough that no
 expert testimony is needed.” (citation omitted)); Inline
 Plastics Corp. v. Lacerta Grp., LLC, 
97 F.4th 889, 897
 (Fed.
 Cir. 2024).
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 NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC         9



     Indeed, one of our cases already resolves this exact
 issue. In WCM Industries, Inc. v. IPS Corporation, we
 found:
     [O]ur precedent does not require opinion testimony,
     and certainly does not require expert opinion
     testimony, for a finding of equivalence. Rather,
     “[p]roof can be made in any form: through
     testimony of experts or others versed in the
     technology; by documents, including texts and
     treatises; and, of course, by the disclosures of the
     prior art.” . . . [W]here the technology is “easily
     understandable without the need for expert
     explanatory testimony,” expert testimony is not
     required.
 
721 F. App’x 959
, 966–67 (Fed. Cir. 2018) (citations
 omitted). While this decision is non-precedential, I find
 that it accurately characterizes our precedent which,
 again, largely speaks in terms of “evidence” generally, or at
 times “testimony,” but not expert testimony specifically.
 Maj. Op. 21–22, 35–37 (collecting cases on testimony
 generally).
      The majority rationalizes its new rule of “evidentiary
 requirements” by reasoning that the doctrine of
 equivalents itself is “conceptually difficult” and therefore
 “the difficulties and complexities of the doctrine require”
 rigid rules. Maj. Op. 21, 37. The majority goes on, stating
 that: “The difficulties and complexities of the doctrine are
 present regardless of the simplicity of the underlying
 technology.” Maj. Op. 37. I disagree. The majority claims
 its new rule is necessary so that experts may ease the jury’s
 burden of understanding the complexity of a legal doctrine.
 But our law does not require, and in fact it chastises,
 witnesses who testify as to the meaning of legal doctrines
 themselves. See Fed. R. Evid. 702 (An expert witness must
 “help the trier of fact to understand the evidence or to
 determine a fact in issue.” (emphasis added)); see also
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 10     NEXSTEP, INC. v. COMCAST CABLE COMMUNICATIONS, LLC




 Stobie Creek Invs. LLC v. United States, 
608 F.3d 1366
,
 1383–84 (Fed. Cir. 2010) (The district court properly
 excluded expert testimony that “would not assist the court
 because the opinion concerned a question of law, not fact.”
 (citation and internal quotation marks omitted)). Instead,
 the proper way to remedy the complexity of legal doctrines
 is for the district court to instruct the jury on the law, as
 the district court did here. Trading Techs. Int’l, Inc. v.
 eSpeed, Inc., 
595 F.3d 1340, 1360
 (Fed. Cir. 2010) (An
 expert cannot “usurp the district court’s role of instructing
 the jury on the law.”). At least in the Third Circuit, the law
 recognizes the role and resolve of the jury and will not,
 absent compelling reasons not presented here, reverse a
 jury verdict that stands on substantial evidence.
                           *   *   *
     This    case   does    not     present    extraordinary
 circumstances. Because I believe the majority invades the
 province of the jury by overturning a reasonable verdict
 that is supported by substantial evidence in this case and
 by imposing an unnecessary new rule in all future doctrine
 of equivalents cases to come, I respectfully dissent in part.