DCT

8:18-cv-01527

Centre One v. AT&T Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 8:18-cv-01527, C.D. Cal., 08/27/2018
  • Venue Allegations: Plaintiff alleges venue is proper in the Central District of California because Defendants operate equipment, data centers, call centers, and retail stores within the district, and place the accused products into the stream of commerce directed at the district.
  • Core Dispute: Plaintiff alleges that Defendant’s Voice-over-Internet-Protocol (VoIP) products and services infringe five patents related to technology for interfacing traditional public switched telephone networks (PSTN) with modern Internet Protocol (IP) networks.
  • Technical Context: The technology at issue is foundational to VoIP services, which enable voice calls to be transmitted over packet-switched data networks like the internet and interoperate with the conventional telephone system.
  • Key Procedural History: The complaint notes that two of the asserted patents, the '667 and '668 patents, were previously the subject of patent reexaminations initiated during a 2009 lawsuit against other parties. Both patents were confirmed as patentable after the proceedings, which may strengthen their presumption of validity but also created extensive prosecution histories that could affect claim scope.

Case Timeline

Date Event
2000-01-07 Priority Date for all Asserted Patents
2006-06-27 U.S. Patent No. 7,068,668 Issued
2009-02-03 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
2018-08-27 Complaint Filed

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

U.S. Patent No. 7,068,668

  • Patent Identification: 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,” issued June 27, 2006.

The Invention Explained

  • Problem Addressed: The patent describes the technical challenge of integrating the legacy circuit-switched PSTN with packet-based IP networks to enable real-time voice communication, noting that the two systems were largely incompatible ('668 Patent, col. 1:24-34). At the time of the invention, this "communication loop" excluded the PSTN, limiting the utility of early internet telephony ('668 Patent, col. 1:21-23).
  • The Patented Solution: The invention discloses a "central communication network" that acts as a bridge between the PSTN and IP networks ('668 Patent, Abstract; Fig. 2). This network uses a computer-controlled switch, a gateway to convert signals between the networks, and a gatekeeper to manage call functions like address translation and admission control, thereby allowing seamless, real-time communication and advanced services across both network types ('668 Patent, col. 5:25-40).
  • Technical Importance: This architecture aimed to unify previously siloed communication platforms, enabling hybrid services like "follow-me" calling where an incoming call could ring on a user's PSTN phone and IP-based device simultaneously ('668 Patent, col. 6:51-68).

Key Claims at a Glance

  • The complaint asserts infringement of at least independent claim 3, as amended by an Inter Partes Reexamination Certificate issued June 12, 2013 (Compl. ¶39, ¶42).
  • The essential elements of claim 3 include:
    • A system comprising a computer-controlled switch connected to a PSTN and gate interface circuitry connected to an IP network.
    • The switch stores destination addresses on both the PSTN and IP network for each subscriber.
    • The switch automatically routes a received call to a subscriber's destination address.
    • The switch can simultaneously route an incoming call to a plurality of pre-designated PSTN and IP destinations.
    • The gate interface circuitry includes gateway and gatekeeper components for interfacing the networks and performing call management functions (e.g., address translation, admission control).
    • A voice response unit is connected between the circuitry and the switch to convert voice signals to digital tones.

U.S. Patent No. 7,486,667

  • Patent Identification: 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,” issued February 3, 2009.

The Invention Explained

  • Problem Addressed: The patent addresses the need for a unified method to manage real-time calls and messages for a subscriber who has endpoints on both the PSTN and an IP network ('667 Patent, col. 1:15-20).
  • The Patented Solution: The patent describes a method for routing calls directed to a subscriber who has both a PSTN number and an IP address ('667 Patent, Claim 1). The system automatically routes the call to these destinations and, if unanswered, takes a message that can be delivered in various formats (voice, email, or facsimile) as determined by the subscriber ('667 Patent, Claim 1).
  • Technical Importance: This invention focuses on the methodology of providing unified communications, giving subscribers flexible control over how they receive calls and messages across traditionally separate networks ('667 Patent, col. 7:1-16).

Key Claims at a Glance

  • The complaint asserts infringement of at least claim 14 (Compl. ¶48, ¶10).
  • The Inter Partes Reexamination Certificate for the '667 Patent, issued September 16, 2013, cancelled original claims 1-13 and added new claim 14 ('667 Reexam Cert., p. 2).
  • Claim 14, as issued, begins: "The method of claim 4 or 6, further comprising..." ('667 Reexam Cert., p. 2). As claims 4 and 6 were cancelled in the same reexamination proceeding, this raises a threshold question as to whether claim 14 has a valid antecedent basis.

Multi-Patent Capsule

  • U.S. Patent No. 8,125,982 B2

    • Identification: “Method and Apparatus for Interfacing a Public Switched Telephone Network and an Internet Protocol Network for Multi-Media Communication,” issued February 28, 2012.
    • Technology Synopsis: The patent discloses systems and methods for bridging PSTN and IP networks, with a specific focus on providing caller identification for calls after they have been routed by a computer-controlled switch (Compl. ¶53).
    • Asserted Claims: At least claim 1 (Compl. ¶54).
    • Accused Features: AT&T's networks and infrastructure are alleged to implement the claimed system, including the storage of destination addresses and post-routing caller identification functions (Compl. ¶54).

  • U.S. Patent No. 8,724,643 B2

    • Identification: “Providing Real-Time Voice Communication Between Devices Connected to an Internet Protocol Network and Devices Connected to a Public Switched Telephone Network,” issued May 13, 2014.
    • Technology Synopsis: This patent covers systems and methods for converting voice signals to packetized digital data signals (and vice versa) to interface IP and PSTN networks, providing call control and routing to one or more stored destination addresses for each subscriber (Compl. ¶59).
    • Asserted Claims: At least claims 10 and 11 (Compl. ¶60).
    • Accused Features: AT&T's networks and infrastructure are alleged to perform the claimed method steps, including signal conversion and routing to stored subscriber addresses (Compl. ¶60).

  • U.S. Patent No. 9,774,745 B2

    • Identification: “Providing Real-Time Voice Communication Between Devices Connected to an Internet Protocol Network and Devices Connected to a Public Switched Telephone Network,” issued September 26, 2017.
    • Technology Synopsis: The patent claims a system where a local gateway at the customer premise packetizes voice information from a telephone and transmits it over an IP network to a computer-controlled switch, enabling communication with the PSTN without requiring a private branch exchange (PBX) (Compl. ¶65).
    • Asserted Claims: At least claim 1 (Compl. ¶66).
    • Accused Features: AT&T's networks and infrastructure are alleged to comprise the components and functionality of this PBX-less system architecture (Compl. ¶66).

III. The Accused Instrumentality

Product Identification

  • The complaint names a range of "AT&T Residential and Business VoIP products and services," including AT&T Phone (formerly U-verse Voice), Business VoIP, Hosted VoIP, and others (Compl. ¶29). These are collectively termed "the Accused Products."

Functionality and Market Context

  • The Accused Products operate on AT&T's "Global MPLS IP network" to provide voice communication between IP-based devices and PSTN-based devices (Compl. ¶30). The system functions by using customer-premise equipment, such as an "AT&T managed router or gateway," to convert analog voice into packetized data (Compl. ¶31, ¶35).
  • This data is routed over AT&T's core network, which uses components like "edge routers, border gateway, provider router, call control element, and/or routing engine" to manage call control, quality, and routing, and to interface with the PSTN (Compl. ¶31). The services also provide advanced features such as voicemail-to-text, simultaneous ringing of multiple numbers, and web portals for feature management (Compl. ¶33, ¶37).
  • The complaint positions AT&T as the "largest telecommunications company in the world" and its services as operating on a "nationwide and global" scale, suggesting significant commercial importance (Compl. ¶6, ¶30).
  • No probative visual evidence provided in complaint.

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... AT&T's network infrastructure includes "switches, call control elements, routing engines, and application servers" to provide call routing, control, and quality functions. ¶31, ¶42 col. 6:5-12
gate interface circuitry... includ[ing] gateway circuitry for interfacing... and gatekeeper circuitry for performing address translation, admission control, bandwidth management and zone management... AT&T's infrastructure uses "edge routers, IP border elements, and network gateway border elements" that perform signal conversion and call control functions between the IP and PSTN networks. ¶31, ¶35, ¶41 col. 6:13-24
said computing controlled switch containing, for each subscriber, destination addresses on the PSTN and the IP network AT&T subscribers are assigned PSTN phone numbers and their devices have IP addresses; the network stores and uses these for services like "simultaneous ringing of multiple stored phone numbers." ¶31, ¶33, ¶41 col. 6:55-62
wherein said computer controlled switch... simultaneously routes the call to a plurality of pre-designated destination addresses on the IP network, on the PSTN, or on both... AT&T's services, such as "simultaneous ringing," are alleged to route a single incoming call to multiple subscriber endpoints on both IP and PSTN networks. ¶33, ¶37, ¶41 col. 6:62-68
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 AT&T's systems are implemented with a voice response unit for converting voice signals into digital tones for use by the computer-controlled switch. ¶41 col. 6:26-30
  • Identified Points of Contention:
    • Scope Question: A primary issue may be whether AT&T's modern, distributed network, comprising geographically separate "edge routers," "border gateways," and "application servers" (Compl. ¶31), can be mapped to the more centralized "computer controlled switch" and "gate interface circuitry" depicted in the patent's figures and description. The defense may argue a mismatch in architecture.
    • Technical Question: What evidence does the complaint provide that AT&T's various network components function collectively as the single, integrated "system" required by the claim, rather than as a collection of standard, off-the-shelf components operating independently according to industry protocols like SIP (Compl. ¶7, ¶26)?

V. Key Claim Terms for Construction

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

    • Context and Importance: The definition of this term is critical. A narrow definition tied to a single, co-located piece of hardware could favor the defendant, whereas a broader, functional definition encompassing a distributed system of cooperating elements could favor the plaintiff. Practitioners may focus on this term because the accused system is a modern, cloud-based network, while the patent's disclosure is from an earlier technological era.
    • Intrinsic Evidence for a Broader Interpretation: The patent describes the switch by its function, namely performing "Class 5 switching" ('668 Patent, col. 6:5-6), a high-level service category not tied to a specific hardware box.
    • Intrinsic Evidence for a Narrower Interpretation: The patent's Figure 2 depicts the "SWITCH" (101) as a discrete architectural block, distinct from the "COMPUTER CONTROL" (109) and "GATEWAY" (105), which could support an argument that it is a specific, unitary component.

  • The Term: "simultaneously routes" ('668 Patent, Claim 3)

    • Context and Importance: The meaning of "simultaneously" will be a key point of dispute. AT&T may argue its "sequential ringing" feature (Compl. ¶33) is not simultaneous, while the plaintiff will likely argue that "simultaneous ringing" (Compl. ¶33) meets the limitation and that the term does not require perfect, instantaneous routing.
    • Intrinsic Evidence for a Broader Interpretation: The specification describes the goal of a "follow me" service where a call can be routed to multiple locations to find the subscriber, which does not necessarily imply exact temporal identity in the routing action ('668 Patent, col. 6:51-54).
    • Intrinsic Evidence for a Narrower Interpretation: A lay reading of "simultaneously" implies actions occurring at the exact same time. The defense may argue that network latencies and protocols make truly simultaneous routing impossible and that the term requires something more than rapid succession.

VI. Other Allegations

  • Indirect Infringement: The complaint does not include counts for indirect infringement and does not plead the specific elements of knowledge and intent for inducement or contributory infringement.
  • Willful Infringement: The complaint does not allege pre-suit knowledge of the asserted patents. It makes a general request for enhanced damages and a finding of an exceptional case in the prayer for relief (Compl. p. 18, ¶b, ¶d), which suggests a claim for willfulness, likely based on alleged infringement occurring after the filing of the lawsuit.

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

  1. Claim Validity: The most immediate question is a legal one for the '667 Patent: can an infringement claim be sustained on asserted claim 14, which appears on its face to be an improper dependent claim whose antecedent basis was cancelled during reexamination? This issue is likely to be addressed in early motion practice.
  2. Architectural Scope: A central factual and legal question for the remaining patents will be one of definitional mapping: can the claims, which describe a system architecture with elements like a "computer controlled switch" and "gate interface circuitry," be construed to read on AT&T's modern, distributed, and standards-based VoIP network, or is there a fundamental mismatch between the patented invention and the accused system?
  3. Impact of Reexamination: A key strategic question will be how the extensive prosecution histories from the prior reexaminations of the '668 and '667 patents affect the case. Arguments made by the patentee to overcome prior art will likely be used by the defense to argue for a narrow claim construction and to assert prosecution history estoppel, potentially limiting the scope of the claims.