PTAB

IPR2016-01425

D Link Systems Inc v. Chrimar Systems Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Equipment Identification in an Ethernet Network
  • Brief Description: The ’012 patent describes systems and methods for identifying Ethernet data terminal equipment connected to a network. The invention centers on adapting terminal equipment with a path having a specific impedance, allowing distinguishing information about the equipment to be associated with that impedance for purposes like asset tracking and management.

3. Grounds for Unpatentability

Ground 1: Obviousness over Chang in view of Patton - Claims 31, 34-36, 40, 43, 44, 52, 56, and 60 are obvious over Chang alone or in view of Patton.

  • Prior Art Relied Upon: Chang (Patent 5,991,885) and Patton (Patent 5,121,482).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Chang teaches nearly all elements of the challenged claims. Chang discloses a network system that detects the presence of remote terminals (e.g., 10Base-T/100Base-T computers) connected via standard RJ45 connectors. Critically, Chang teaches distinguishing between different types of remote terminals by using different continuous presence signal voltages (e.g., 3VDC vs. 5VDC). Petitioner contended that this voltage-based differentiation is inherently "associated to impedance," as voltage and impedance are fundamentally related electrical properties, thus meeting the core limitation of independent claim 31. Chang was also alleged to teach the features of the dependent claims, including the use of RJ45 connectors (claim 34), resistors in the detection path (claim 40), and a controller (claim 43). To the extent Chang’s voltage-based detection is not considered impedance-based, Patton was cited as teaching an explicit impedance-based detection mechanism for connected devices in a LAN environment.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Chang and Patton because both address the same problem of device detection in LANs. Chang itself discusses Patton’s impedance-based detection mechanism as a known method. A POSITA would have recognized Patton's impedance-based circuitry as a known and suitable alternative to Chang's voltage-based detection method to achieve the same goal of distinguishing between connected devices.
    • Expectation of Success: A POSITA would have a reasonable expectation of success in incorporating Patton's impedance-based detection into Chang's system, as it involved applying a known detection technique in its conventional environment to achieve a predictable result.

Ground 2: Obviousness over De Nijs in view of Chaudhry - Claims 31, 35, 36, 43, 56, and 60 are obvious over De Nijs alone or in view of Chaudhry.

  • Prior Art Relied Upon: De Nijs (Patent 5,568,525) and Chaudhry (Patent 5,790,363).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that De Nijs teaches a method for automatically configuring network equipment by detecting an "identifying characteristic" of a connected workstation. De Nijs explicitly discloses that this characteristic can be a "characteristic impedance" and provides examples of distinguishing between different workstations, including an "Ethernet workstation," based on their distinct and detectable impedances. This was argued to directly teach the central limitation of claim 31, where distinguishing information is associated with impedance. De Nijs further discloses that this impedance detection is part of a protocol to determine how to connect the device to the network, satisfying claim 35. Chaudhry was cited for its disclosure of overvoltage/overcurrent protection circuitry for standard 10Base-T Ethernet networks, a common feature in such systems.
    • Motivation to Combine: A POSITA would combine the teachings because both De Nijs and Chaudhry operate in the same technical field: Local Area Networks (LANs) using twisted-pair wiring, specifically in 10Base-T Ethernet environments. A POSITA would be motivated to add known, conventional protection circuitry, as taught by Chaudhry, to the network configuration system of De Nijs to improve its robustness and protect it from electrical damage. This represents a common and predictable design choice.
    • Expectation of Success: Adding standard protection circuitry to a network device is a routine engineering task. A POSITA would have a high expectation of success in integrating Chaudhry's protection system with De Nijs's detection system without undue experimentation, as the components are designed to work in the same standard Ethernet environment.

4. Key Claim Construction Positions

  • "wherein distinguishing information ... is associated to impedance within the at least one path" (Claim 31c): Petitioner argued this limitation should be construed as a non-limiting statement of intended use rather than a structural limitation. The Petitioner contended the phrase does not describe an action the equipment itself performs but rather describes a property of the equipment intended for a particular use. As an apparatus claim must distinguish over the prior art based on structure, Petitioner argued this functional language should not be given patentable weight.

5. Relief Requested

  • Petitioner requests the institution of an inter partes review and the cancellation of claims 31, 34-36, 40, 43, 44, 52, 56, and 60 of the ’012 patent as unpatentable.