Court Opinion

ID: 9941575
Source: CourtListenerOpinion
Date Created: 2024-02-16 16:02:24.675978+00
Date Added: 2024-06-11T13:46:46.773734
License: Public Domain

Case: 22-1939    Document: 56    Page: 1   Filed: 02/16/2024

   United States Court of Appeals
       for the Federal Circuit
                 ______________________

        PROMPTU SYSTEMS CORPORATION,
               Plaintiff-Appellant

                            v.

   COMCAST CORPORATION, COMCAST CABLE
          COMMUNICATIONS, LLC,
             Defendants-Appellees
            ______________________

                       2022-1939
                 ______________________

    Appeal from the United States District Court for the
 Eastern District of Pennsylvania in No. 2:16-cv-06516-JS,
 Chief Judge Juan R. Sanchez.
                  ______________________

                Decided: February 16, 2024
                 ______________________

      J. MICHAEL JAKES, Finnegan, Henderson, Farabow,
 Garrett & Dunner, LLP, Washington, DC, argued for plain-
 tiff-appellant.   Also represented by CHRISTOPHER
 BLACKFORD; BENJAMIN SCHLESINGER, Atlanta, GA; JACOB
 ADAM SCHROEDER, Palo Alto, CA.

     MARK ANDREW PERRY, Weil, Gotshal & Manges LLP,
 Washington, DC, argued for defendants-appellees. Also
 represented by JOSHUA HALPERN; IAN ANTHONY MOORE,
 New York, NY.
                 ______________________
Case: 22-1939    Document: 56     Page: 2   Filed: 02/16/2024

 2   PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION

  Before MOORE, Chief Judge, PROST and TARANTO, Circuit
                        Judges.
 TARANTO, Circuit Judge.
     In December 2016, Promptu Systems Corp. filed a com-
 plaint against Comcast Corp. in the Eastern District of
 Pennsylvania alleging that Comcast had infringed
 Promptu-owned U.S. Patent Nos. 7,047,196 and 7,260,538
 and also asserting infringement of U.S. Reissued Patent
 No. RE44,326 and certain state-law bases for relief. In
 June 2022, before completion of discovery or any summary-
 judgment proceedings, but after the district court adopted
 claim constructions that largely followed Comcast’s pro-
 posals, Promptu and Comcast jointly stipulated to the
 with-prejudice dismissal of Promptu’s ’326 patent-infringe-
 ment claim and state-law claims. Based on the set of claim
 constructions adopted by the district court, Promptu also
 stipulated to and moved for entry of a final judgment of no
 infringement by Comcast of the ’196 and ’538 patents. The
 district court granted Promptu’s request and entered final
 judgment.
     Promptu appeals the judgment, challenging several of
 the underlying claim constructions. We conclude that the
 district court incorrectly construed certain claim terms.
 We therefore vacate the judgment and remand for further
 proceedings.
                              I
                             A
     The ’196 patent begins its Summary of the Invention
 by stating that “[a]n embodiment of the invention provides
 speech recognition services to a collection of users over a
 network that supports cable television and/or video deliv-
 ery.” ’196 patent, col. 5, lines 3–5. The patent identifies
 two relevant problems not solved in the prior art. First,
 sophisticated speech-recognition technology “requires state
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 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION               3

 of the art processing software and hundreds of megabytes
 of RAM to support” it, which, the patent implies, prior-art
 set-top cable boxes typically could not provide. Id., col. 1,
 lines 54–56; see also id., col. 1, lines 30–62. Second, per-
 forming speech recognition at a centralized processing site,
 instead of on a user’s set-top box, requires the efficient up-
 stream transmission (“from subscriber to cable plant”), us-
 ing “limited bandwidth,” of speech commands and content
 from many users simultaneously, which, the patent says,
 prior-art cable systems typically could not provide. Id., col.
 2, lines 63–65; see also id., col. 2, line 60, through col. 3, line
 41. The patent specifically notes that, in one prior-art sys-
 tem cited as an example, upstream transmission “is quite
 inefficient due to the number of collisions which ensue, e.g.
 simultaneous transmissions from different set-top boxes
 which interfere with one another,” which “leads to typical
 channel utilization on the order of just 30%.” Id., col. 3,
 lines 33–38.
      The patent addresses the first problem through “a
 speech recognition system that is centrally located in or
 near a wireline node” or is “centrally located in or near a
 server farm,” “a web-site hosting facility,” or “a network
 gateway”—i.e., through performing speech recognition at a
 powerful remote computer, instead of at a local set-top box.
 Id., col. 5, lines 11–17. This “speech recognition and iden-
 tification engine . . . is capable of processing thousands of
 speech commands simultaneously” and thus serving many
 users. Id., col. 5, lines 27–29. The patent addresses the
 second problem by using “a back channel containing a mul-
 tiplicity of identified speech channels” where the “back
 channel is from a multiplicity of user sites.” Id., col. 22,
 lines 8–15; id., fig.10. Regarding how to achieve that
 many-in-one arrangement, the patent states that one
 method of doing so “may” be through the partitioning
 scheme—using both frequency and time-slot assignment—
 set out in U.S. Patent Application No. 09/664,874 (incorpo-
 rated by reference in the ’196 patent). See id., col. 27, lines
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 4   PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION

 48–54 (’196 patent incorporating the ’874 application by
 reference); J.A. 6898–929 (the ’874 application). 1
     Claims 1 and 53 are representative of the asserted
 claims of the ’196 patent for present purposes:
     1. A method of using a back channel containing a
     multiplicity of identified speech channels from a
     multiplicity of user sites presented to a speech pro-
     cessing system at a wireline node in a network sup-
     porting at least one of cable television delivery and
     video delivery, comprising the steps of:
         receiving said back channel to create a re-
         ceived back channel;
         partitioning said received back channel
         into a multiplicity of received identified
         speech channels;
         processing said multiplicity of said received
         identified speech channels to create a mul-
         tiplicity of identified speech content; and
         responding to said identified speech con-
         tent to create an identified speech content
         response that is unique, for each of said
         multiplicity of identified speech contents.
 ’196 patent, col. 50, line 62, through col. 51, line 10 (empha-
 sis added).

     1    Several times the patent specification gives the ti-
 tle of the ’874 application with the number of U.S. Patent
 Application No. 09/679,115. See, e.g., ’196 patent, col. 27,
 lines 49–53; id., col. 28, lines 1–3, 14–16, 39–42. Promptu
 explained that those references are to the ’874 application.
 Promptu Opening Br. at 47 n.1. Comcast does not disagree.
 Comcast Opening Br. at 32–33.
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 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION          5

     53. A method of operating at least part of a speech
     recognition system coupled to a wireline node in a
     network, comprising the steps of:
         processing a multiplicity of received identi-
         fied speech channels to create a multiplicity
         of identified speech content; and
         responding to said identified speech con-
         tent to create an identified speech content
         response that is unique to each of said mul-
         tiplicity of identified speech contents;
         wherein said speech recognition system is
         provided said multiplicity of received iden-
         tified speech channels based upon a re-
         ceived back channel at said wireline node
         from a multiplicity of user sites coupled to
         said network;
         wherein said network supports at least one
         of the collection comprising: cable televi-
         sion delivery to said multiplicity of user
         sites; and video delivery to said multiplicity
         of user sites.
 Id., col. 58, lines 12–29 (emphasis added).
                               B
     The ’538 patent describes and claims related subject
 matter, but the ’538 patent’s specification is materially dif-
 ferent from the ’196 patent’s specification. At a general
 level, the primary distinction between the ’196 patent and
 the ’538 patent is that the former relates to using remote
 voice-recognition systems to deliver requested (cable or
 video) content in response to a user’s speech request, while
 the latter relates to using remote voice-recognition systems
 to control a user’s television set based on a user’s speech
 command. See, e.g., ’538 patent, col. 2, lines 21–39.
     Claim 34 is representative for present purposes:
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 6   PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION

     34. A centralized multi-user voice operated televi-
     sion control system, comprising:
         television remote controls configured to di-
         rectly and wirelessly control television sets
         and additionally to receive user voice input
         and wirelessly transmit first output repre-
         sentative of the voice input to television
         set-top boxes;
         television set top boxes configured to re-
         ceive television input signals via cable tel-
         evision link and provide television output
         signals compatible with television sets, the
         set top boxes additionally responsive to re-
         ceiving the first output from the television
         remote controls to transmit representative
         second output to a central processing sta-
         tion via the cable television link;
         a centralized processing station configured
         to receive and process second output from a
         multitude of television set top boxes by ap-
         plying voice recognition to the second out-
         put to identify user-intended voice
         commands, to derive set-top-box-compati-
         ble instructions to carry out the identified
         voice commands, and returning signals
         representing the instructions to respective
         top boxes via the cable television link;
         where the set top boxes are further respon-
         sive to receiving the signals representing
         the instructions from the central pro-
         cessing station to execute the instructions.
 Id., col. 13, lines 37–61 (emphasis added).
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 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION        7

                              C
     In December 2016, Promptu filed a complaint against
 Comcast in the Eastern District of Pennsylvania alleging,
 among other things, that Comcast had infringed the ’196
 and ’538 patents. J.A. 506. That litigation was stayed (at
 Promptu’s request, with Comcast’s agreement) between
 July 2018 and September 2020 after Comcast filed with the
 Patent and Trademark Office (PTO) eight petitions seeking
 review of the asserted patents: six for inter partes reviews
 (IPRs) under 35 U.S.C. §§ 311–19, and two for covered
 business method (CBM) reviews under § 18 of the Leahy-
 Smith America Invents Act, Pub. L. No. 112-29, 125 Stat.
 284, 329–31 (2011). See J.A. 4839–48; J.A. 5144 (schedul-
 ing order noting the stay had been lifted). We have twice
 heard appeals from the PTO proceedings involving the ’196
 patent. See Comcast Cable Communications, LLC v.
 Promptu Systems Corp., 838 F. App’x 551 (Fed. Cir. 2021);
 Promptu Systems Corp. v. Comcast Cable Communications,
 LLC, No. 2022-1093, 2024 WL 163326 (Fed. Cir. Jan. 16,
 2024) (argued here the same day, before the same panel, as
 the present appeal). We have heard one appeal from the
 PTO proceedings involving the ’538 patent. See Comcast
 Cable Communications, LLC v. Promptu Systems Corp.,
 838 F. App’x 555 (Fed. Cir. 2021).

     In May 2022, the district court issued claim construc-
 tion orders, and in June 2022, the court issued a memoran-
 dum opinion explaining its claim constructions. The court
 largely adopted Comcast’s proposed constructions of the
 claim terms in the ’196 and ’538 patents now at issue before
 us. See Promptu Systems Corp. v. Comcast Corp., No. 16-
 cv-06516, slip op. at 1–2 (E.D. Pa. May 12, 2022), ECF No.
 299 (Claim Construction Order); Promptu Systems Corp. v.
 Comcast Corp., No. 16-cv-06516 (E.D. Pa. May 19, 2022),
 ECF No. 301 (amending Claim Construction Order);
 Promptu Systems Corp. v. Comcast Corp., No. 16-cv-06516,
 slip op. at 4–18 (E.D. Pa. June 10, 2022), ECF No. 315
 (Memorandum Opinion).
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 8   PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION

     Thereafter, Promptu and Comcast jointly stipulated to
 the with-prejudice dismissal of Promptu’s ’326 patent-in-
 fringement claim and state-law claims.            J.A. 9530.
 Promptu also stipulated to and moved for entry of final
 judgment on its ’196 and ’538 patent-infringement claims
 “as a result of non-infringement by Comcast . . . based on
 the Court’s Claim Construction Order,” stating that it
 aimed to seek appellate review of at least four of the under-
 lying claim constructions. J.A. 9530. In response, on June
 16, 2022, the district court dismissed Promptu’s ’326 pa-
 tent-infringement claim and its state-law claims with prej-
 udice, and it directed entry of final judgment for Comcast
 on Promptu’s ’196 and ’538 patent-infringement claims.
 See Promptu Systems Corp. v. Comcast Corp., No. 16-cv-
 06516, slip op. at 1 (E.D. Pa. June 16, 2022), ECF No. 316.
     Promptu filed a timely notice of appeal from the district
 court’s final judgment on June 21, 2022, J.A. 9449–51,
 within the thirty days allowed by 28 U.S.C. § 2107(a). The
 district court had jurisdiction under 28 U.S.C. § 1338, and
 we have jurisdiction under 28 U.S.C. § 1295(a)(1).
                               II
     On appeal, Promptu challenges the district court’s con-
 struction of four claim limitations: “back channel,” “multi-
 plicity of received identified speech channels,” “speech
 recognition system coupled to a wireline node” (each from
 the ’196 patent), and “centralized processing station” (from
 the ’538 patent). For the “multiplicity of received identified
 speech channels” phrase, Promptu’s challenge relates to
 the meaning of the “speech channels” term. For the
 “speech recognition system coupled to a wireline node”
 phrase, Promptu separately challenges the district court’s
 construction with respect to the meanings of the “speech
 recognition system,” “coupled to,” and “wireline node”
 terms.
     “Where, as here, a plaintiff concedes noninfringement
 by stipulation, we need only address the district court’s
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 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION        9

 construction of the pertinent claims.” Starhome GmbH v.
 AT&T Mobility LLC, 743 F.3d 849, 854 (Fed. Cir. 2014).
 “We review claim construction based on intrinsic evidence
 de novo and review any findings of fact regarding extrinsic
 evidence for clear error.” Grace Instrument Industries,
 LLC v. Chandler Instruments Co., 57 F.4th 1001, 1008
 (Fed. Cir. 2023). “We generally give words of a claim their
 ordinary meaning in the context of the claim and the whole
 patent document; [and] the specification particularly, but
 also the prosecution history, informs the determination of
 claim meaning in context, including by resolving ambigui-
 ties”; but “even if the meaning is plain on the face of the
 claim language, the patentee can, by acting with sufficient
 clarity, disclaim such a plain meaning or prescribe a spe-
 cial definition.” World Class Technology Corp. v. Ormco
 Corp., 769 F.3d 1120, 1123 (Fed. Cir. 2014) (citing Phillips
 v. AWH Corp., 415 F.3d 1303, 1312–17 (Fed. Cir. 2005) (en
 banc); Thorner v. Sony Computer Entertainment America
 LLC, 669 F.3d 1362, 1365 (Fed. Cir. 2012)); see Personal-
 ized Media Communications, LLC v. Apple Inc., 952 F.3d
 1336, 1339–40 (Fed. Cir. 2020). In this matter, prosecution
 history has played no substantial role in the parties’ con-
 tentions.
                              A
     We first conclude that the district court erred by nar-
 rowly construing “back channel” in the ’196 patent as lim-
 ited to “[a] fixed band of frequencies or time slot(s) for
 transmitting signals to a speech processing system or en-
 gine.” Claim Construction Order, at 2 (emphasis added).
                              1
     Nothing in the claim language suggests the limitation
 to a fixed band of frequencies or time slots. “Back” undis-
 putedly refers to the direction (upstream) opposite the di-
 rection of transmission of the programming (downstream).
 And whether “channel” means a path or what is flowing in
 the path (an issue discussed infra), we see nothing in the
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 10 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION

 meaning of the quite general term “channel” that limits the
 path to one defined by a fixed band of frequencies or time
 slots.
      Nor does the ’196 patent’s specification require the par-
 ticular path-definition technique demanded by the district
 court’s claim construction. The patent discusses the back
 channel, which contains a multiplicity of speech channels,
 broadly, defined by beginning at a user site (or sites) and
 ending at a speech processing system. See, e.g., ’196 pa-
 tent, col. 50, lines 62–66; id., col. 22, lines 8–14. It recog-
 nizes the possibility of using different protocols or formats,
 including conversion between these, along different “sub-
 sections” of the path or route from user site to speech recog-
 nition system. See, e.g., id., col. 9, line 48, through col. 10,
 line 13 & fig.3 (describing passage through a “gateway” be-
 tween different kinds of networks); id., col. 12, lines 57–65
 (similar); id., col. 10, lines 54–61 (describing how “[s]peech
 commands” may be “converted to digital signals” from “an-
 alog” or “preprocessed” including by “conversion to an al-
 ternative form of speech representation”).             It also
 recognizes use of the DOCSIS cable-modem protocol, id.,
 col. 11, lines 51–59, which it is undisputed need not, though
 can, use fixed frequency bands or time slots. Though “for-
 mats” and “protocols” may not be synonymous with “chan-
 nels,” what the discussion indicates is breadth regarding
 techniques for the back channel. And there is no stated
 narrowing to a fixed frequency band or time slots.
     Moreover, the ’196 patent, through the incorporated
 ’874 application, describes schemes that involve signal
 transmission along the back channel on dynamically as-
 signed and managed (i.e., not fixed) frequency bands or
 time slots. See, e.g., J.A. 6904–05 (describing a system
 where the “head-end receiver” performs “active frequency
 management of the upstream transmission spectrum” us-
 ing “an allocation table . . . to keep track of the assignments
 of channels by storing a mapping between each channel
 and the set-top box to which the channel is assigned”); J.A.
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 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION          11

 6906–10 (same for a “headend controller” that controls the
 “management and assignment of time slots”); cf. J.A. 6904
 (mentioning a transmission scheme that involves “enabling
 each set-top box to perform frequency hopping”). And Com-
 cast’s expert—when addressing the ’196 patent’s descrip-
 tion of a “Speech Packet Processor” that may “capture and
 prepare the upstream speech packets that are to be fed to
 the Speech Recognition Engine,” ’196 patent, col. 18, lines
 20–23—explained that “[s]uch packets may, or may not, be
 sent upstream using defined frequency bands, or ‘chan-
 nels.’” J.A. 8215 ¶ 7 (emphasis added).
      Use of a fixed frequency band or time slots, in this pa-
 tent, is no more than exemplary, not required. The speci-
 fication certainly refers to such use in describing
 embodiments. See, e.g., ’196 patent, col. 5, lines 22–26
 (“This system is unique in that the speech command which
 originates at the user site . . . is sent upstream via the re-
 turn path (often five to 40 MHz) in the cable system to a
 central speech recognition and identification engine.”); id.,
 col. 44, lines 37–38 (“Each NTSC television channel has ap-
 proximately 6 MHz of bandwidth.”); id., col. 31, lines 33–35
 (“The multiplexing mechanism onto channel 1332 may per-
 form time division multiplexing.”). But the specification
 does not limit the channel-defining techniques to a fixed
 frequency band or time slots. Similarly, the word “channel”
 also can be used to refer to particular frequencies or bands
 or time slots, as indicated by dictionaries on which Comcast
 relies. See, e.g., J.A. 2695, 2724, 2783; Comcast Response
 Br. at 23 (stating that “the district court’s construction is a
 common meaning of ‘channel’ in the relevant field of art”
 (emphasis added)). But the dictionaries do not limit “chan-
 nel” to such techniques for defining a path for signal trans-
 mission. See, e.g., J.A. 6729. And the district court made
 no finding that no other such techniques were known to
 relevant artisans at the time relevant to construing this
 patent.
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 12 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION

     Our case law has long recognized that particular fea-
 tures recited in the specification merely as aspects of em-
 bodiments, and not expressly or even implicitly identifying
 requirements of the invention, do not narrow a claim term
 that is otherwise broader in its ordinary meaning. See, e.g.,
 Phillips, 415 F.3d at 1323; Liebel-Flarsheim Co. v. Medrad,
 Inc., 358 F.3d 898, 904–09 (Fed. Cir. 2004); Sjolund v. Mus-
 land, 847 F.2d 1573, 1582 (Fed. Cir. 1988) (reciting the
 “general principle” that “limitations from the specification
 are not to be read into the claims”). That principle controls
 the claim construction of “back channel” here. The princi-
 ple was important in several cases argued to us by Comcast
 and Promptu the same day as this one, where Comcast suc-
 ceeded in defending unpatentability rulings of the Patent
 Trial and Appeal Board by resisting various arguments
 made by Promptu to limit claim terms’ scope to features of
 embodiments found in the specification. 2 Here, where in-
 fringement is at stake, it is Comcast that is seeking a nar-
 rowing to embodiment features. We find the arguments for
 narrowing in this case are no more justified than the ones
 rejected in the Board matters.
                              2
     That conclusion suffices to reject the construction of
 “back channel” adopted by the district court. The parties
 also dispute whether “channel” in that phrase refers to a
 path in which a data stream flows (as Comcast says) or,
 instead, to the data stream that flows in the path (as
 Promptu says). Compare Comcast Response Br. at 28
 (“[T]he data are not the channel.”), with Promptu Reply Br.
 at 18 (“Promptu’s construction of ‘back channel’ as a stream

     2   See, e.g., Promptu Systems Corp. v. Comcast Cable
 Communications, LLC, No. 2020-1253, 2024 WL 163327
 (Fed. Cir. Jan. 16, 2024) (affirming decision of Board in
 CBM2018-00034); Promptu, 2024 WL 163326 (affirming
 decision of Board in IPR2018-00344).
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 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION            13

 conveys both concepts. A communication stream does not
 exist without data flowing through it, and that data neces-
 sarily follows a path from a source to a destination.” (cita-
 tion omitted)). We leave this dispute to be addressed, if
 necessary, on remand.
      For one thing, the proper resolution of the dispute is
 far from clear in light of the limited attention given to it
 here. For example, sometimes the ’196 patent specification
 seems to use “channel” to refer to the path. See, e.g., ’196
 patent, col. 3, lines 11–43 (referring to “channel utilization
 on the order of just 30%” due to signal interference between
 users; transmitting request signals “whether or not the
 transmission channel is already in use”; and stating that
 “[d]ownstream control data transmission typically occurs
 in a separate frequency band from the upstream chan-
 nels”). On the other hand, while the patent sometimes re-
 fers to processing or receiving “signals” or a “stream” (or
 “channel stream”), e.g., id., col. 12, lines 21, 39, 47, 57–62;
 id., col. 42, lines 33–34, 41–49; id., col. 47, line 29, the pa-
 tent also frequently refers to “processing” or “receiving” a
 “channel,” which tends to suggest that “channel,” at least
 in those references, means the data stream, not the path (it
 being awkward to describe a path as being processed or,
 perhaps, received), see, e.g., id., Abstract; id., figs.10, 11B,
 18B; id., col. 2, lines 30–31; id., col. 4, lines 27, 32–33; id.,
 col. 22, lines 25–26, 31–32, 46–48; id., col. 23, lines 3–14;
 id., col. 25, lines 55–60; id., col. 40, lines 4–5, 17–19, 24–31;
 id., col. 51, lines 1–7 (claim 1). Relatedly, we described the
 patent’s phrase “received back channel” as the “back chan-
 nel” at a later point in time, Comcast, 838 F. App’x at 554,
 and that phrase has now been given an unchallenged con-
 struction as meaning “[d]ata received via the back chan-
 nel,” Claim Construction Order, at 2—in which the “data”
 term seems to use “channel” to refer to data while the “via
 the back channel” phrase seems to use “channel” to refer to
 the path.
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 14 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION

     Although “[w]hen the parties present a fundamental
 dispute regarding the scope of a claim term, it is the court’s
 duty to resolve it,” courts “are not (and should not be) re-
 quired to construe every limitation present in a patent’s as-
 serted claims.” O2 Micro International Ltd. v. Beyond
 Innovation Technology Co., 521 F.3d 1351, 1362 (Fed. Cir.
 2008). The purpose of claim construction is to resolve “dis-
 puted meanings and technical scope, to clarify and when
 necessary to explain what the patentee covered by the
 claims, for use in the determination of infringement” or in-
 validity. U.S. Surgical Corp. v. Ethicon, Inc., 103 F.3d
 1554, 1568 (Fed. Cir. 1997). Accordingly, “only those terms
 need be construed that are in controversy, and only to the
 extent necessary to resolve the controversy.” Vivid Tech-
 nologies, Inc. v. American Science & Engineering, Inc., 200
 F.3d 795, 803 (Fed. Cir. 1999).
      Here, it is not clear how significant this path-versus-
 stream dispute is as a practical matter. Promptu’s counsel
 stated during oral argument that, although it is crucial to
 decide whether a “back channel” requires fixed frequency
 bands or time slots, it might not be necessary to decide
 whether the “back channel” is a path or route or is instead
 the stream (alone or in combination with its path). Oral
 Arg. at 7:05–8:00. In these circumstances, we leave any
 resolution of this aspect of the parties’ dispute for the dis-
 trict court to consider on remand.
                               B
     We similarly reject the district court’s construction of
 the “multiplicity of received identified speech channels”
 phrase in the ’196 patent as requiring “a single band of fre-
 quencies or a designated time slot” for each identified
 speech channel. Claim Construction Order, at 2 (emphasis
 added). This construction depends on the underlying con-
 struction of “channel,” which we have rejected. There is no
 stronger reason to limit an identified speech channel to a
 single frequency band or designated time slot than to limit
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 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION          15

 the “back channel” as the rejected claim construction of
 that phrase does.
     We also note that the district court required, in the pre-
 sent construction, that “each channel” is “assigned to a par-
 ticular user site.” Id. But the ’196 patent contains
 dependent claims that recite the additional limitation that
 “at least one of said identified speech channels has an as-
 sociated user site.” See, e.g., ’196 patent, col. 51, lines 12–
 13. That associated-user-site limitation must therefore be
 presumed absent from the “multiplicity of received identi-
 fied speech channels” phrase that provides its antecedent
 basis. See Karlin Technology, Inc. v. Surgical Dynamics,
 Inc., 177 F.3d 968, 971–72 (Fed. Cir. 1999) (“[L]imitations
 stated in dependent claims are not to be read into the inde-
 pendent claim from which they depend.”). We see no suffi-
 cient justification for requiring “each channel” to be
 “assigned to a particular user site.”
                               C
     The district court construed the “speech recognition
 system coupled to a wireline node” phrase in the ’196 pa-
 tent, in sum, as “a system whose function is speech recog-
 nition” “connected in or near” “a network node providing
 video or cable television delivery to multiple users using a
 wireline physical transport between those users at the
 node.” Claim Construction Order, at 2. That construction
 incorrectly construes the constituent terms “speech recog-
 nition system,” “coupled to,” and “wireline node” within the
 claim phrase.
                               1
     The district court’s construction of “speech recognition
 system” as “a system whose function is speech recognition”
 improperly presupposes that speech recognition is the ex-
 clusive function of the speech recognition system. Claim
 Construction Order, at 2 (emphasis added). The claim
 term, “speech recognition system,” does not entail such
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 16 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION

 exclusivity—which Comcast itself did not urge. Further,
 the ’196 patent’s specification describes functions that a
 “[s]peech processor computer” may perform other than
 speech recognition, such as billing and system manage-
 ment. See, e.g., ’196 patent, col. 36, lines 24–34; id., col. 41,
 lines 8–40.
     We do not go further to find words for a proper con-
 struction to replace the one we reject. The parties have not
 adequately explored alternatives, and again we are not
 sure what aspects of the phrase need clarification for reso-
 lution of the liability issues. Additional exploration should
 take place on remand, to the extent necessary, of the best
 way to characterize the limitation of “system” effected by
 the use of the phrasal modifier “speech recognition.” It may
 be relevant that the specification indicates that the slightly
 longer phrase, “speech recognition processor system,” does
 not encompass the remote-control device, the televisions,
 the telephone, the optical nodes, the set-top box, the gate-
 way, the server farm, or the server array—which are de-
 picted as distinct elements separate from the “speech
 recognition processor system.” ’196 patent, fig.3. Im-
 portantly, a claim construction, if needed at all, should help
 resolve, not add to, uncertainty in the understanding the
 finder of fact is to use in applying a claim term.
                                2
     The district court’s construction of “coupled to” as “con-
 nected in or near” incorrectly reads a proximity require-
 ment (“in or near”) into the claim term at issue. Claim
 Construction Order, at 2. We have several times held var-
 iants of “coupled to” in patent claims before us to mean
 simply “connected to.” See General Electric Co. v. Interna-
 tional Trade Commission, 685 F.3d 1034, 1045 (Fed. Cir.
 2012) (“[T]he term ‘coupled with’ indicates a connection.”);
 Johnson Worldwide Associates, Inc. v. Zebco Corp., 175
 F.3d 985, 992 (Fed. Cir. 1999) (“[T]he unmodified term ‘cou-
 pled’ generically describes a connection, and does not
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 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION         17

 require a mechanical or physical coupling.”). We see no
 sufficient reason to add a proximity requirement here.
       The ’196 patent describes, for example, a “coupling”
 that may involve “wireless physical transport,” ’196 patent,
 col. 10, lines 62–66, or a “server farm” with “communica-
 tively coupled” servers, id., col. 9, lines 59–61. The ’196
 patent’s specification states that “[t]he invention comprises
 . . . a speech recognition system that is centrally located in
 or near a wireline node” but also states that the “speech
 recognition system may also be centrally located in or near
 a server farm[,] a website hosting facility, or a network
 gateway.” Id., col. 5, lines 11–17. Setting aside that “cen-
 trally located” is not the claim term—“coupled to” is—the
 statement that a speech recognition system may be located
 “in or near” sites other than the wireline node further im-
 plies that proximity between the speech recognition system
 and the wireline node (via coupling) is not required.
     We construe “coupled to” as meaning “connected to.”
                               3
     The district court improperly adopted the specifica-
 tion’s definition of “centralized wireline node” when con-
 struing the claim term “wireline node.” Memorandum
 Opinion, at 13 (emphasis added); ’196 patent, col. 1, line
 66, through col. 2, line 2 (“[A] centralized wireline node re-
 fers to a network node providing video or cable television
 delivery to multiple users using a wireline physical
 transport between those users at the node.”). The “central-
 ized” modifier (used in the composite term defined in the
 specification) must add some meaning to or limitation on
 the “wireline node” being modified. The absence of the
 “centralized” modifier in the claims, in turn, means that
 the claimed “wireline node” must be broader in some way
 than the “centralized wireline node” defined in the specifi-
 cation. See Johnson, 175 F.3d at 989 (“[M]odifiers will not
 be added to broad terms standing alone.”). We see nothing
 troubling about a patent defining a modified term in the
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 18 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION

 specification and then using that term without modifica-
 tion in the claims, particularly since a single patent speci-
 fication may provide support for a variety of continuation
 and continuation-in-part applications as claims are ac-
 cepted, rejected, and amended throughout prosecution.
     Promptu’s proposed construction (“node connected by a
 wire, as opposed to a wireless connection,” Memorandum
 Order, at 12) is consistent with the scope of the claim lan-
 guage and specification, and we adopt it here.
                              D
     Promptu challenges two aspects of the district court’s
 claim construction of “centralized processing station” in the
 ’538 patent as a “device at a cable-TV network head-end
 unit that receives and performs voice recognition on voice
 commands, and generates and returns instructions to set-
 top boxes to carry out the commands.” Memorandum Opin-
 ion, at 7. The first aspect challenged is the location re-
 quirement: that a “centralized processing station” must be
 located “at a cable-TV network head-end unit.” Id. The
 second aspect challenged is the function requirement: that
 the “centralized processing station” itself “performs voice
 recognition on voice commands.” Id. at 8–9. We affirm the
 latter aspect of the claim construction (the function re-
 quirement) but reverse the former aspect (the location re-
 quirement).
     The district court correctly understood that the claim
 language, read as a whole, specifies that the “centralized
 processing station” (or some element of it) performs the re-
 cited speech recognition. Claim 34, for example, states that
 the “centralized processing station” is “configured to re-
 ceive and process” output “by applying voice recognition”
 “to identify” voice commands and “to derive set-top-box-
 compatible instructions.” ’538 patent, col. 13, lines 51–58
 (emphasis added). Particularly because it is the “central-
 ized processing station” that is itself “configured to” per-
 form the required voice-recognition actions (i.e., to receive
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 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION           19

 and process output by applying voice recognition, to iden-
 tify voice commands, and to derive instructions), the claims
 fairly specify that the “centralized processing station” per-
 forms the claimed voice recognition, rather than merely ap-
 plies the results of such voice recognition performed
 elsewhere.
     In contrast, we conclude that, when construing “cen-
 tralized processing station,” the district court incorrectly
 required the recited “device” to be located “at a cable-TV
 head-end unit.” Memorandum Opinion, at 7. It is clear
 that a “head-end unit” and a “centralized processing sta-
 tion” are different things: the two phrases are different
 claim elements used in separate claims throughout the ’538
 patent. See Tandon Corp. v. U.S. International Trade
 Commission, 831 F.2d 1017, 1023 (Fed. Cir. 1987) (“There
 is presumed to be a difference in meaning and scope when
 different words or phrases are used in separate claims.”).
 The district court did not disagree. Rather, the court con-
 cluded that these separate claim elements must be colo-
 cated.
     The district court relied on the specification’s state-
 ment that “[t]he voice command is then transmitted, for ex-
 ample, to a central processing station located at a cable
 television head-end unit,” ’538 patent, col. 2, lines 29–32;
 Memorandum Opinion, at 7–8, as support for its determi-
 nation that the “centralized processing station” is located
 by definition at the head-end unit. Additionally, the speci-
 fication cites element 160 in figure 1 as labelling both “a
 head-end unit 160” and “the central processing station
 160.” See ’538 patent, col. 4, lines 4, 8–9, 20; id., fig.1. But
 those bases, we conclude, are insufficient for the conclusion
 drawn by the district court.
     As confirmed by the “for example” language, the colo-
 cation noted in the above quoted sentence is merely exem-
 plary. ’538 patent, col. 2, lines 29–32. And the use of a
 single figure-element number when referring to the
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 20 PROMPTU SYSTEMS CORPORATION v. COMCAST CORPORATION

 centralized processing station and the head-end unit like-
 wise need not mean anything more than that, in the em-
 bodiment illustrated in figure 1, the two components are
 colocated. Neither of those specification sources implies
 that the two components must be colocated.
     Such a limitation would read embodiment features into
 a claim term that is not so limited. The “centralized” term
 in “centralized processing station,” as the claim language
 makes clear, refers simply to its relation to a group of set-
 top boxes. See Comcast Response Br. at 61 (“The claim
 term ‘centralized processing station’ makes clear that the
 processing station is a discrete physical thing (a ‘station’)
 that is centrally located (‘centralized’) vis-à-vis the ‘multi-
 tude of television set top boxes’ from which it receives sig-
 nals.” (citing ’538 patent, col. 13, lines 37–61)). Such
 centralization exists when the station is in the cable net-
 work, serving many set-top boxes, whether or not it is lo-
 cated at the same place as a head-end unit.
                               III
      We vacate the district court’s entry of final judgment
 as it relates to Promptu’s ’196 and ’538 patent-infringe-
 ment claims. We reverse in part and affirm in part the dis-
 trict court’s claim constructions. We remand to the district
 court for further proceedings.
     The parties shall bear their own costs.
      VACATED IN PART, REVERSED IN PART,
       AFFIRMED IN PART, AND REMANDED