DCT

1:25-cv-00898

CelluPlex LLC v. Grandstream Networks Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-00898, D. Del., 07/18/2025
  • Venue Allegations: Plaintiff alleges venue is proper in the District of Delaware because Defendant is incorporated in Delaware and has engaged in systematic and continuous business activities in the district.
  • Core Dispute: Plaintiff alleges that Defendant's products infringe a patent related to an interface device that connects a cellular telephone to a wired telephone network, allowing users to make and receive cellular calls via conventional wired handsets.
  • Technical Context: The technology addresses the convergence of cellular and landline telephony within a home or office, aiming to provide the convenience of using a single cellular number with the ergonomic and system benefits of a traditional wired phone network.
  • Key Procedural History: The complaint does not mention any prior litigation, Inter Partes Review (IPR) proceedings, or licensing history related to the patent-in-suit.

Case Timeline

Date Event
2003-11-10 ’664 Patent Priority Date (Application Filing)
2007-02-13 ’664 Patent Issue Date
2025-07-18 Complaint Filing Date

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

U.S. Patent No. 7,177,664 - Bluetooth interface between cellular and wired telephone networks

  • Patent Identification: U.S. Patent No. 7,177,664, "Bluetooth interface between cellular and wired telephone networks," issued February 13, 2007.

The Invention Explained

  • Problem Addressed: The patent describes a scenario where individuals who own cellular telephones often turn them off when at home or in the office to conserve battery, causing them to miss incoming calls. Furthermore, making calls on a cellular phone can be less convenient than using a full-featured conventional wired telephone. (’664 Patent, col. 1:11-29).
  • The Patented Solution: The invention is an "interconnect device" that wirelessly links a user's cellular phone to their existing wired telephone network (e.g., home phones or an office PBX system) using a short-range radio protocol like Bluetooth. (’664 Patent, Abstract). This device makes the cellular line available as if it were a standard landline; a user can pick up any wired phone, get a dial tone, and make a call through their cellular service. Incoming cellular calls cause the wired phones to ring, allowing the user to answer on any handset. (’664 Patent, col. 2:35-47; Fig. 1).
  • Technical Importance: The technology allows a user to consolidate their communications onto a single cellular number while leveraging the superior ergonomics and features (e.g., speakerphones, multi-line capability) of their existing wired telephone system. (’664 Patent, col. 2:25-34).

Key Claims at a Glance

  • The complaint asserts "one or more claims," including "exemplary method claims," but does not specify them in the body of the complaint (Compl. ¶11). Independent claims 1 (apparatus) and 13 (method) are representative of the patented invention.
  • Independent Claim 1 (Apparatus):
    • A first short-range radio transceiver for exchanging signals with a second transceiver in a cellular phone.
    • An interface connected to the first transceiver and a wired telephone network.
    • The interface "emulating a wired line connection" to a central office.
    • The interface includes means for handling outgoing calls (indicating line availability, receiving a dialed number, and transmitting it to the cell phone).
    • The interface also includes means for handling incoming calls (applying a ringing signal, establishing an audio channel when a wired phone goes off-hook, and disconnecting the channel when it goes on-hook).
  • The complaint does not explicitly reserve the right to assert dependent claims.

III. The Accused Instrumentality

Product Identification

The complaint refers to "Exemplary Defendant Products" but identifies them only within an "Exhibit 2" that is incorporated by reference and was not attached to the publicly filed complaint (Compl. ¶11, ¶13).

Functionality and Market Context

The complaint does not provide sufficient detail for analysis of the accused product's specific functionality or market context, as these details are allegedly contained within the unprovided Exhibit 2 (Compl. ¶13). The allegations are limited to general statements that the products are made, used, and sold by the Defendant (Compl. ¶11).

IV. Analysis of Infringement Allegations

The complaint alleges that the "Exemplary Defendant Products practice the technology claimed by the ’664 Patent" and that claim charts demonstrating this are included in an unprovided Exhibit 2 (Compl. ¶13). Because the complaint provides only conclusory allegations of infringement and the referenced claim chart exhibit is not available, a detailed element-by-element analysis is not possible. The narrative theory is that the accused products "satisfy all elements of the Exemplary '664 Patent Claims" through their normal operation (Compl. ¶13).

No probative visual evidence provided in complaint.

  • Identified Points of Contention: Based on the patent and the general nature of the allegations, the infringement analysis may raise several questions:
    • Scope Questions: Claim 1 is written in a "means-plus-function" format. A central issue will be identifying the structure in the specification corresponding to the claimed "means" (e.g., "means for applying a ringing signal") and determining whether the accused products contain equivalent structures. (’664 Patent, col. 10:5-9).
    • Technical Questions: A key factual question will be what specific components and software routines in the Defendant's products perform the functions claimed, such as "emulating a wired line connection" and "receiving a telephone number to be called from the wired telephone." (’664 Patent, col. 8:55-56; col. 8:65-67). The complaint does not provide the evidence that will be used to prove these functions are performed.

V. Key Claim Terms for Construction

  • The Term: "short-range radio transceiver" (Claim 1)

  • Context and Importance: This term defines the core communication link. Its construction is critical to determine if the claims are limited to the patent's preferred Bluetooth embodiment or if they can read on other wireless technologies. Practitioners may focus on this term because the patent's title specifies "Bluetooth," but the claim language itself is broader.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The claim uses the generic term "short-range radio transceiver" without specifying a protocol. The specification notes that while the preferred embodiment uses Bluetooth, the invention is not necessarily limited to it. (’664 Patent, col. 2:48-54).
    • Evidence for a Narrower Interpretation: The patent is titled "Bluetooth interface..." and the detailed description and message-exchange diagrams (Figs. 3 and 4) are explicitly based on the "Bluetooth Telephony Control protocol Specification." (’664 Patent, Title; col. 4:51-58). A party could argue that the invention is defined by and limited to the specific Bluetooth context disclosed.

  • The Term: "emulating a wired line connection from said wired telephone to a telephone central office" (Claim 1)

  • Context and Importance: This term describes the fundamental function of the interface. The dispute will likely center on how closely the device must mimic a traditional telephone line to satisfy this limitation.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: A party might argue this simply requires providing functions a user would expect from a phone line, such as providing a dial tone and processing dialed digits, without requiring specific electrical mimicry. (’664 Patent, col. 2:58-61).
    • Evidence for a Narrower Interpretation: The specification discusses emulating specific, technical line types, such as a "conventional loop start line," "POTS (plain old telephone system) line," "ground start and E&M trunks," and "ISDN." (’664 Patent, col. 4:15-27). A party could argue that "emulating" requires replicating the signaling characteristics of one of these specific, disclosed standards.

VI. Other Allegations

  • Indirect Infringement: The complaint does not include a count for indirect infringement and does not plead the required elements of knowledge or intent for inducement or contributory infringement.
  • Willful Infringement: The complaint does not allege willful infringement. It requests that the case be declared "exceptional" under 35 U.S.C. § 285, which is a basis for seeking attorney's fees, but does not provide a factual basis for willfulness, such as allegations of pre-suit knowledge of the patent. (Compl. ¶E.i).

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

  1. Definitional Scope: A primary issue will be claim construction, specifically whether the term "short-range radio transceiver" is limited to the heavily-disclosed Bluetooth protocol or can be interpreted more broadly, and what technical functions are required to meet the limitation of "emulating a wired line connection."
  2. Sufficiency of Allegations: Given the complaint’s reliance on an unprovided exhibit, an early focus of the case may be on the sufficiency of the pleadings and whether the Plaintiff has provided adequate notice of its infringement theory.
  3. Structural Equivalence: For the "means-plus-function" limitations in Claim 1, a central evidentiary question will be whether the accused products contain hardware and software that is structurally equivalent to the specific implementations disclosed in the ’664 patent for performing the claimed functions.