Cisco Systems Inc v. Chrimar Systems Inc

1. Case Identification

• Case #: IPR2018-01511
• Patent #: 8,902,760
• Filed: August 3, 2018
• Petitioner(s): Cisco Systems Inc.
• Patent Owner(s): ChriMar Systems, Inc.
• Challenged Claims: 73, 106, 112, 134, 142, 145, and 146

2. Patent Overview

• Title: Network System and Optional Tethers
• Brief Description: The ’760 patent relates to systems and methods for networking computer equipment over pre-existing wiring. The technology centrally involves "phantom powering," where DC power is supplied to remote network devices over the same twisted-pair conductors used for Ethernet data communications.

3. Grounds for Unpatentability

Ground 1: Claims 73, 106, 112, 134, 142, and 145 are obvious over Hunter in view of Bulan.

• Prior Art Relied Upon: Hunter (WO 96/23377) and Bulan (Patent 5,089,927).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Hunter disclosed a system for supplying DC "phantom power" over an Ethernet cable from a central hub to remote terminal equipment (TE). The combination with Bulan, which disclosed an improved current control apparatus (CCA), rendered the claims obvious. The petition contended that the Board had previously found the original version of claim 73 obvious over this combination, and the only new limitation added during re-examination—that the central equipment is a "BaseT Ethernet hub"—was explicitly taught by Hunter. The combined system, using Bulan’s CCA, could detect different magnitudes of current drawn by the TE (which contains a DC-DC converter) to distinguish between normal start-up inrush currents, operational faults, and normal operating current.
  • Motivation to Combine: A POSITA would combine these references to improve the rudimentary overcurrent protection in Hunter. Hunter’s system used a simple thermistor or polyfuse, which could not distinguish between a harmless, high-current DC-DC converter start-up and a damaging short circuit. Bulan was directed specifically to solving this known problem by providing a superior CCA that intelligently manages different current-draw scenarios. Therefore, substituting Bulan’s advanced CCA for Hunter's basic protective device was a simple replacement of one known element with an improved version to gain predictable benefits.
  • Expectation of Success: Petitioner asserted a high expectation of success, as Bulan's CCA was designed as a one-for-one replacement for existing, less-sophisticated current-limiting circuits in phantom-powered systems like Hunter's.

Ground 2: Claim 146 is obvious over Hunter in view of Bulan, further in combination with Nelson.

• Prior Art Relied Upon: Hunter (WO 96/23377), Bulan (Patent 5,089,927), and Nelson (Patent 4,823,070).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the Hunter/Bulan combination to address claim 146, which required the TE to have a path to "change impedance... in response to the at least one DC condition." Petitioner contended that the TE in the Hunter/Bulan system would necessarily include a DC-DC converter to regulate the incoming phantom power. Nelson was introduced as it disclosed the fundamental building blocks of such converters: switching voltage regulators. Nelson explicitly taught that its voltage regulators function by changing impedance (by switching transistors, resistors, or inductive/capacitive networks) in response to an input DC voltage (a DC condition) to maintain a constant output voltage.
  • Motivation to Combine: The motivation to combine Hunter and Bulan was previously established. A POSITA would have been further motivated to incorporate the teachings of Nelson because any practical implementation of the DC-DC converter in the Hunter/Bulan TE would require a voltage regulator to function properly. Using a well-understood voltage regulator circuit as taught by Nelson was a necessary and obvious design choice to make the conceptual system of Hunter/Bulan operable.
  • Expectation of Success: The combination was a straightforward application of known, fundamental circuit components (voltage regulators) to implement a described system (a phantom-powered TE), leading to a high expectation of success.

Ground 3: Claim 146 is obvious over Bloch in view of IEEE 802.3 and Peguiron.

• Prior Art Relied Upon: Bloch (Patent 4,173,714), IEEE 802.3 (1993 and 1995 editions), and Peguiron (CH 643 095 A5).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued Bloch taught a phantom circuit for supplying power and bi-directional data over the same conductors in a telephone system, where the terminal unit modulated its impedance to send status data. The IEEE 802.3 standard provided the necessary context to apply Bloch’s phantom power concept to a modern BaseT Ethernet network, which used hubs, specific twisted-pair wiring, and standard connectors. Peguiron was added to teach an interrogation protocol where a central unit sends a DC interrogation signal containing a specific address, and only the addressed terminal responds by changing its impedance to transmit data back. This combination taught changing impedance in response to a DC condition (the interrogation signal) in an Ethernet context.
  • Motivation to Combine: A POSITA would combine Bloch with the IEEE 802.3 standard to achieve the known benefit of powering network devices over standard Ethernet cables, eliminating separate power supplies and conserving connector pins. Peguiron would be incorporated to improve upon Bloch’s less efficient time-division data signaling. Peguiron's interrogation protocol conserved network bandwidth—a key design consideration—by allowing the central hub to request data on-demand rather than having all terminals constantly transmit status updates.
  • Expectation of Success: Combining these known techniques—phantom powering, Ethernet standards, and interrogation protocols—involved applying established principles to improve network efficiency and functionality, with predictable and successful results.

4. Key Claim Construction Positions

• "BaseT": Petitioner proposed this term be construed as "twisted pair Ethernet in accordance with the 10Base-T or 100Base-T standards."
• "part of a detection protocol" (Claim 134): Proposed as representing "an intended use of the different magnitudes of current flow... for detecting current/impedance or a change in current/impedance."
• "powered off" (Claim 145): Proposed as "without operating power," clarifying that this allows applying power to a component (like a DC-DC converter during startup) but not full operating power to the network equipment itself.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §314(a) or §325(d) was inappropriate. The challenged claims were amended during a re-examination that occurred concurrently with a prior IPR (the "Juniper IPR"). In that proceeding, the Board found the original claims unpatentable over the same Hunter/Bulan prior art. However, the Board held it could not rule on the validity of the amended claims because they were not part of the original petition. This petition therefore presented the Board with its first opportunity to review the patentability of the newly amended claims in view of this art, meaning the arguments were not redundant or previously considered against these specific claims.

6. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 73, 106, 112, 134, 142, 145, and 146 of Patent 8,902,760 as unpatentable.