Securus Technologies Inc v. DSI ITI LLC

1. Case Identification

• Case #: IPR2017-02169
• Patent #: 7,826,604
• Filed: October 2, 2017
• Petitioner(s): Securus Technologies, Inc.
• Patent Owner(s): Global Tel*Link Corporation
• Challenged Claims: 1-12

2. Patent Overview

• Title: Steganographic Techniques for Telephone Calls
• Brief Description: The ’604 patent describes systems and methods for embedding identification data into a telephone signal using steganography, specifically spread spectrum modulation. The technique aims to make the identification data imperceptible to human listeners while allowing a receiver to extract the data for purposes such as detecting the addition of a third party, monitoring phone usage, or identifying unauthorized calls from restricted callers.

3. Grounds for Unpatentability

Ground 1: Obviousness over Lee, Hopper, and Neubauer - Claims 1 and 3-6 are obvious over Lee in view of Hopper and Neubauer.

• Prior Art Relied Upon: Lee (Patent 6,792,030), Hopper (Patent 3,406,344), and Neubauer (Patent 6,584,138).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the combination of these references taught all limitations of independent claim 1. Lee was asserted to teach a system for unobtrusively transmitting data during a telephone call using spread spectrum modulation, including generating identification data, subdividing it, encoding it onto a carrier, adding it to a telephone signal, and transmitting it. Hopper was cited for its disclosure of transmitting data signals that accompany voice transmission to identify the source of a telephone call, such as to trace annoying calls. While Lee and Hopper taught signals that were "virtually unnoticeable" or "virtually undiscernible," Neubauer was introduced for its teaching of a specific coding method that renders a data signal completely "non-audible" and "not perceptible to the human ear."
  • Motivation to Combine: A person of ordinary skill in the art (POSA) would combine Lee and Hopper because they address the same problem of imperceptibly transmitting data over a voice channel. A POSA would have been motivated to implement Lee's spread spectrum system to transmit the source-identifying data taught by Hopper to identify the origin of nuisance calls. A POSA would then incorporate Neubauer's coding scheme to improve upon the "virtually unnoticeable" signal of Lee, making it completely imperceptible, which was a known goal in the art.
  • Expectation of Success: A POSA would have had a reasonable expectation of success because combining the references involved applying known techniques (Hopper's source identification, Neubauer's inaudible coding) to an existing, suitable system (Lee's spread spectrum framework) to achieve predictable results.

Ground 2: Obviousness over Lee, Hopper, Neubauer, and Horne - Claims 2, 7, and 8 are obvious over the combination of Ground 1 in view of Horne.

• Prior Art Relied Upon: Lee (Patent 6,792,030), Hopper (Patent 3,406,344), Neubauer (Patent 6,584,138), and Horne (Patent 6,298,122).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the combination in Ground 1, which established a method for transmitting source-identifying data. Petitioner argued that Horne supplied the missing limitations of dependent claims 2, 7, and 8: comparing the assembled identification data to a "predetermined set of restricted data" and initiating a response. Horne disclosed a call screening system that compares incoming Caller ID information to a database of "allowable calling parties" and can take action, such as disconnecting a call from a "totally blocked" party or routing it to an answering machine.
  • Motivation to Combine: A POSA would have been motivated to add Horne's call-screening functionality to the base system of Lee/Hopper/Neubauer as a natural extension. Once a system can identify a caller's source, it is a small, logical step to use that information to automatically screen calls against a list of restricted numbers. Lee itself suggests the extracted data can be "acted upon if necessary," and Horne provides a well-known method for doing so.
  • Expectation of Success: Integrating a known call-screening module (Horne) with a known data transmission system (Lee/Hopper/Neubauer) was a straightforward application of existing technologies with predictable outcomes.

Ground 3: Obviousness over Lee, Hopper, and Horne - Claims 9-12 are obvious over Lee and Hopper in view of Horne.

• Prior Art Relied Upon: Lee (Patent 6,792,030), Hopper (Patent 3,406,344), and Horne (Patent 6,298,122).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground challenged independent claims 9 and 11, and their dependents. Petitioner asserted the arguments were analogous to those in Grounds 1 and 2. The combination of Lee and Hopper taught the core method of generating, encoding, and transmitting source-identifying data from a source telephone to a destination telephone. Horne again provided the teachings of analyzing the extracted data against a "predetermined set of restricted data" and initiating a "restricted call response," such as disconnecting the call, to determine if the use was unauthorized.
  • Motivation to Combine: The motivation was the same as in Ground 2: it would have been obvious to a POSA to combine a system that identifies a caller (Lee/Hopper) with a system that screens callers based on that identity (Horne) to achieve automated call monitoring and restriction.
  • Expectation of Success: As with the other grounds, the combination involved integrating known components to perform their established functions, leading to a high expectation of success.

4. Key Claim Construction Positions

• "imperceptible to a human listener": Petitioner argued this term should be construed to be met if any human listener is unable to perceive the signal. However, Petitioner contended that even under a more restrictive standard where the signal must be imperceptible to most or all listeners, the prior art—particularly Neubauer, which explicitly teaches a method for making a data signal non-audible—disclosed this feature.
• "adding (or combining) the modulated identification signal": Petitioner asserted this phrase should be understood as passively adding the identification signal to the telephone signal without modifying the underlying speech content. This construction was based on the ’604 patent’s own disclosure, which expressed a preference for passive addition to preserve the integrity of a recorded conversation for potential use as evidence.

5. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-12 of Patent 7,826,604 as unpatentable.