DCT

8:19-cv-02422

Centre One v. Comcast Cable Communications LLC

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 8:19-cv-02422, C.D. Cal., 12/16/2019
  • Venue Allegations: Plaintiff alleges venue is proper in the Central District of California because Defendant Comcast maintains regular and established places of business in the district, including Xfinity retail stores and customer service centers, from which it offers for sale and services the accused products.
  • Core Dispute: Plaintiff alleges that Defendant’s VoIP telecommunications services and related network infrastructure infringe seven patents related to technology for interfacing traditional public switched telephone networks (PSTN) with modern internet protocol (IP) networks.
  • Technical Context: The technology at issue involves Voice over Internet Protocol (VoIP), which enables voice communication over packet-switched IP networks, and its integration with the legacy circuit-switched PSTN that has historically formed the backbone of public telecommunications.
  • Key Procedural History: The complaint notes that two of the asserted patents, U.S. Patent Nos. 7,068,668 and 7,486,667, were the subject of a 2009 lawsuit against other telecommunications companies. During that litigation, both patents underwent inter partes reexamination at the U.S. Patent and Trademark Office and were subsequently confirmed as patentable, a fact that may be raised to counter potential invalidity arguments in this case.

Case Timeline

Date Event
2000-01-07 Priority Date for all Asserted Patents
2006-06-27 U.S. Patent No. 7,068,668 Issued
2009-01-01 Prior lawsuit filed involving the '667 and '668 Patents (approximate date)
2009-02-03 U.S. Patent No. 7,486,667 Issued
2012-02-28 U.S. Patent No. 8,125,982 Issued
2013-06-12 Reexamination Certificate Issued for '668 Patent
2013-09-16 Reexamination Certificate Issued for '667 Patent
2014-05-13 U.S. Patent No. 8,724,643 Issued
2017-09-26 U.S. Patent No. 9,774,745 Issued
2018-08-28 U.S. Patent No. 10,063,710 Issued
2019-08-06 U.S. Patent No. 10,375,249 Issued
2019-12-16 Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,068,668 - Method and Apparatus for Interfacing a Public Switched Telephone Network and an Internet Protocol Network for Multi-Media Communication

The Invention Explained

  • Problem Addressed: At the time of the invention, traditional public switched telephone networks (PSTN) and packet-switched IP networks were largely separate and could not be successfully integrated for real-time voice communication, limiting users to siloed communication systems (Compl. ¶27; ’668 Patent, col. 1:44-54).
  • The Patented Solution: The patent describes a system, centered around a computer-controlled switch, that serves as an interface between the PSTN and an IP network. The system employs gate interface circuitry, including a gateway and a gatekeeper, to manage the conversion and routing of calls, allowing for features like simultaneously routing an incoming call to a subscriber’s destinations on both the PSTN (e.g., a landline) and the IP network (e.g., a computer) (’668 Patent, Abstract & Fig. 2). This architecture is designed to enable seamless, real-time voice communication across the two distinct network types (’668 Patent, col. 6:21-42).
  • Technical Importance: This technology provided a technical bridge between the ubiquitous, reliable PSTN and the emerging, flexible IP network, enabling advanced "follow-me" and unified messaging services that were not previously possible (Compl. ¶16, ¶20).

Key Claims at a Glance

  • The complaint asserts at least Claim 3, which was amended during reexamination (Compl. ¶51).
  • The essential elements of independent Claim 3 are:
    • A system comprising a computer-controlled switch operable to receive calls from both an IP network and a PSTN, and to route calls to both networks.
    • Gate interface circuitry connected to the switch, which includes gateway circuitry (for interfacing voice circuits) and gatekeeper circuitry (for address translation, admission control, etc.).
    • A voice response unit connected between the gate interface circuitry and the switch for converting voice signals to digital tones for the switch.
    • The switch is configured to store destination addresses for subscribers on both the PSTN and IP network and simultaneously route incoming calls to a plurality of a subscriber's pre-designated destinations.
  • The complaint expressly reserves the right to assert additional claims (Compl. ¶51).

U.S. Patent No. 7,486,667 - Method and Apparatus for Interfacing a Public Switched Telephone Network and an Internet Protocol Network for Multi-Media Communication

The Invention Explained

  • Problem Addressed: The patent addresses the need for methods to intelligently route real-time voice communications originating from an IP network to a subscriber who may have endpoints on both the IP network and the PSTN, and to gracefully handle calls that are not answered (’667 Patent, col. 1:43-52).
  • The Patented Solution: The patent claims a method for routing a call received from an internet-connected device to a subscriber. The call can be simultaneously directed to both a predesignated IP address and a PSTN number. The method also includes steps for handling unanswered calls by delivering a message in a form determined by the subscriber, such as voice, email, or facsimile (Compl. ¶56; ’667 Patent, col. 8:16-33). Key to the method is the conversion of voice signals to digital tones by a voice response unit to facilitate routing by a switch (’667 Patent, col. 8:43-48).
  • Technical Importance: The invention provided a method for implementing enhanced calling services like simultaneous ringing and unified messaging, improving the user experience and reliability of early VoIP systems (Compl. ¶56).

Key Claims at a Glance

  • The complaint asserts at least Claim 14, which was added during reexamination (Compl. ¶57).
  • The essential elements of independent Claim 14 are:
    • A method comprising converting, at a voice response unit connected at a gateway to a switch, voice signals received by the gateway to digital tones for the switch.
    • Transmitting, at the voice response unit, the digital tones to the switch.
  • The complaint expressly reserves the right to assert additional claims (Compl. ¶57).

U.S. Patent No. 8,125,982

  • Technology Synopsis: Discloses systems and methods for real-time voice communication between IP and PSTN networks that provide caller identification. The system uses a computer-controlled switch to store subscriber destination addresses on both networks and perform caller ID functions upon routing a call (Compl. ¶62).
  • Asserted Claims: At least Claim 1 (Compl. ¶63).
  • Accused Features: The complaint alleges infringement by Comcast’s network infrastructure that accommodates call forwarding and mobile phone calling access through its apps (Compl. ¶63).

U.S. Patent No. 8,724,643

  • Technology Synopsis: Discloses systems and methods for real-time voice communication that entail converting voice signals to packetized digital data to interface the IP network and PSTN. The system routes calls to one or more destination addresses stored for a subscriber (Compl. ¶68).
  • Asserted Claims: At least Claims 10 and 11 (Compl. ¶69).
  • Accused Features: The complaint accuses Comcast’s Residential and Business Products, which operate on a network infrastructure allegedly comprising the claimed components and functional steps (Compl. ¶69).

U.S. Patent No. 9,774,745

  • Technology Synopsis: Discloses a system where a local gateway device packetizes voice information received from a telephone for transmission over an IP network to a computer-controlled switch. The system is specified as operating without the use of a private branch exchange ("PBX") (Compl. ¶74).
  • Asserted Claims: At least Claim 1 (Compl. ¶75).
  • Accused Features: Infringement is alleged by Accused Residential Products, Voice Mobility, VoiceEdge, SIP trunk, and Xfinity Mobile products (Compl. ¶75).

U.S. Patent No. 10,063,710

  • Technology Synopsis: Discloses systems employing gate interface circuitry to receive a call from a device on the IP network, depacketize the voice data, and use a voice response unit to convert the data to digital tones. A computer-controlled switch then uses these tones to route the call to one of a plurality of stored subscriber destination addresses (Compl. ¶80).
  • Asserted Claims: At least Claim 1 (Compl. ¶81).
  • Accused Features: The complaint alleges infringement by all Accused Products operating on Comcast's network (Compl. ¶81).

U.S. Patent No. 10,375,249

  • Technology Synopsis: Discloses systems where a computer control receives a call from a PSTN device and uses gate interface circuitry to packetize and route it over the IP network to a subscriber device. The system also includes a message system that can receive digital tones from the PSTN to identify a second subscriber and send a message over the IP network (Compl. ¶86).
  • Asserted Claims: At least Claim 1 (Compl. ¶87).
  • Accused Features: Infringement is alleged by all Accused Products operating on Comcast's network (Compl. ¶87).

III. The Accused Instrumentality

Product Identification

  • The complaint collectively refers to the accused instrumentalities as the "Accused Products." These are categorized as: "Accused Residential Products" (e.g., Xfinity Voice, Xfinity Connect App), "Accused Business Products" (e.g., Business VoiceEdge, Comcast Business App), and Xfinity Mobile service (Compl. ¶29-32).

Functionality and Market Context

  • The complaint alleges that Comcast’s Accused Products operate on a Hybrid Fiber Coaxial ("HFC") network infrastructure that functions in accordance with PacketCable standards to transmit voice, video, and data (Compl. ¶33). This architecture is designed to accommodate the interconnection of the HFC network with the PSTN through various protocols and signal conversions (Compl. ¶34). The complaint provides a diagram of the PacketCable architecture, showing components such as Media Gateways (MG), Media Gateway Controllers (MGC), and Call Management Servers (CMS) that manage the interface between the IP-based cable network and the PSTN (Compl. p. 10, Fig. 1).
  • Functionally, these products provide VoIP telephony services with enhanced features such as voicemail, call forwarding, caller ID, and simultaneous ringing, which allows a single incoming call to be routed to up to ten different phone numbers on either the IP network or the PSTN (Compl. ¶41, ¶45). The complaint includes a diagram illustrating the architecture of the Comcast Voice Network, depicting the relationship between its HFC network, IP backbone, and interconnections to the PSTN and other peer networks (Compl. p. 12).

IV. Analysis of Infringement Allegations

’668 Patent Infringement Allegations

Claim Element (from Independent Claim 3) Alleged Infringing Functionality Complaint Citation Patent Citation
a computer controlled switch operable for use by subscribers and adapted for connection to a local public switched telephone network, receiving calls from the IP network and the PSTN, and routing calls to the PSTN and the IP network Comcast's network and infrastructure, which includes Call Management Servers (CMS) and other components that route calls between its HFC/IP network and the PSTN. ¶34, ¶36, ¶51 col. 6:21-30
gate interface circuitry... includ[ing] gateway circuitry for interfacing between the IP network and the voice circuits of the PSTN, and gatekeeper circuitry for performing address translation, admission control, bandwidth management and zone management Comcast’s use of network components consistent with the PacketCable standard, including Media Gateways (MG), Media Gateway Controllers (MGC), and Session Border Controllers (SBC). ¶35, ¶36 col. 6:31-42
a voice response unit connected between the gate interface circuitry and the switch for receiving voice signals and converting them to digital tones for the switch The complaint alleges Comcast’s network comprises all claimed components and functionality necessary to accommodate features like simultaneous calling, which rely on such signal conversion for routing. ¶51 col. 6:43-48
wherein said computer controlled switch receives an incoming call... and simultaneously routes the call to a plurality of pre-designated destination addresses on the IP network, on the PSTN, or on both Comcast’s “simultaneous ring” feature, offered with its Business Voice Mobility and Voice Edge Select products, which routes calls to up to ten designated numbers on the IP network or PSTN. ¶45, ¶51 col. 7:4-15

’667 Patent Infringement Allegations

Claim Element (from Independent Claim 14) Alleged Infringing Functionality Complaint Citation Patent Citation
converting, at a voice response unit connected at a gateway to a switch, voice signals received by the gateway to digital tones for the switch Comcast’s network infrastructure is alleged to perform the necessary signal conversions to enable the routing of calls for its various services, including simultaneous calling. ¶57 col. 6:43-48
transmitting, at the voice response unit, the digital tones to the switch The complaint alleges that Comcast’s network performs all functional steps of the claimed method to implement features like simultaneous calling for its Business Voice Mobility and Voice Edge Select products. ¶57 col. 6:43-48

Identified Points of Contention

  • Scope Questions: A central question may be whether the components of Comcast's modern, distributed PacketCable network architecture (e.g., Call Management Servers, Session Border Controllers) correspond to the elements of the claimed “computer controlled switch” and “gatekeeper circuitry,” which are described in the patent in the context of a more centralized, early-2000s VoIP architecture.
  • Technical Questions: The complaint broadly alleges that Comcast's network "comprises each of the components and functionality" of the claimed systems (Compl. ¶51). The analysis may turn on what evidence is presented to show that a specific component or set of components within Comcast's infrastructure performs the function of the "voice response unit" as recited in the claims—specifically, converting voice signals into digital tones for use by the switch.

V. Key Claim Terms for Construction

The Term: "computer controlled switch" (’668 Patent, Claim 3)

  • Context and Importance: This term defines the core routing element of the claimed system. Its construction will be critical in determining whether Comcast's distributed network architecture, which uses components like Call Management Servers (CMS), falls within the scope of a term potentially rooted in more traditional, monolithic switching hardware.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent describes the switch’s function as performing "Class 5 switching of PSTN lines," focusing on its capability rather than its physical form, which may support a functionally broader definition that could encompass a distributed system (’668 Patent, col. 6:22-25).
    • Evidence for a Narrower Interpretation: Figure 2 of the patent depicts the "SWITCH" (101) as a discrete, centralized component distinct from the "COMPUTER CONTROL" (109), "GATEWAY" (105), and other elements. This depiction could be used to argue for a narrower construction requiring a more centralized hardware element.

The Term: "gatekeeper circuitry" (’668 Patent, Claim 3)

  • Context and Importance: The definition of this term is important because the patent ascribes to it specific functions like address translation and admission control. The dispute may focus on whether these functions must be performed by a single, dedicated "gatekeeper" component as contemplated by the H.323 standard referenced in the patent, or if they can be performed by a collection of modern network elements like Session Border Controllers (SBCs) and proxy servers used in SIP-based networks.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claim defines the circuitry by its functions ("performing address translation, admission control, bandwidth management, and zone management"), which could support an interpretation covering any component or set of components that performs these roles (’668 Patent, col. 6:39-42).
    • Evidence for a Narrower Interpretation: The patent specification explicitly discusses the H.323 gatekeeper standard, which may suggest the claim term should be limited to components that operate consistent with that specific protocol, as opposed to the SIP-based protocols the complaint alleges Comcast uses (’668 Patent, col. 3:31-39; Compl. ¶26).

VI. Other Allegations

  • Willful Infringement: The complaint does not contain specific factual allegations to support a claim of willful infringement, such as pre-suit knowledge of the patents-in-suit. However, the prayer for relief requests "enhanced damages as permitted by 35 U.S.C. § 284," reserving the right to seek such damages should evidence of willfulness emerge (Compl. p. 25).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of architectural mapping: can the elements of the asserted claims, conceived in the context of early-2000s VoIP technology (e.g., "computer controlled switch," "gatekeeper"), be mapped onto the components of Comcast’s modern, distributed, and standards-based PacketCable network architecture, or has the technology evolved such that there is a fundamental mismatch?
  • A second key question will be one of evidentiary sufficiency: will the plaintiff be able to demonstrate, with technical specificity, how discrete components within Comcast's complex network perform the functions of each claimed element (such as the "voice response unit"), or will the infringement case hinge on more generalized allegations that the network as a whole inherently practices the patented inventions?
  • Finally, a key legal and strategic question will be the impact of reexamination: how will the successful inter partes reexamination of the two earliest patents-in-suit, which affirmed their validity over cited prior art, shape Comcast’s invalidity defenses and potentially influence settlement discussions?