United Access Tech LLC v. CenturyTel Broadband Services LLC

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: United Access Technologies, LLC (Delaware)
  • Defendant: CenturyLink, Inc. (Louisiana), and its numerous subsidiaries
  • Plaintiff’s Counsel: Stamoulis & Weinblatt LLC
• Case Identification: 1:11-cv-00339, D. Del., 04/15/2011
• Venue Allegations: Plaintiff alleges venue is proper because numerous Defendant entities are incorporated in, have registered agents in, or conduct substantial business in the District of Delaware. The complaint also asserts that venue is convenient because the Court previously presided over related litigation involving the same patents-in-suit.
• Core Dispute: Plaintiff alleges that Defendant’s CenturyLink DSL high-speed internet services infringe patents related to transmitting high-frequency data signals over existing telephone wiring concurrently with voice signals.
• Technical Context: The technology leverages existing copper telephone lines, the "last mile" of telecommunications infrastructure, to deliver broadband data services without requiring the installation of new dedicated cabling like coaxial or fiber optic lines to the premises.
• Key Procedural History: The complaint states that the patents-in-suit were previously litigated in the same court in United Access Tech LLC v. Earthlink Inc, a case that proceeded through claim construction and a February 2007 jury trial. At the time of this complaint's filing, the EarthLink case was pending on appeal at the U.S. Court of Appeals for the Federal Circuit. Prior claim construction rulings may have preclusive effect in this litigation.

Case Timeline

Date	Event
1989-07-14	Earliest Priority Date for all patents-in-suit ('596, '446, '585)
1998-12-01	U.S. Patent No. 5,844,596 Issued
2001-07-05	U.S. Patent No. 6,243,446 Issued
2003-04-01	U.S. Patent No. 6,542,585 Issued
2007-02-01	Jury trial in related EarthLink case
2010-02-01	Ruling on post-trial motions in related EarthLink case
2011-04-15	Complaint Filed

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

U.S. Patent No. 5,844,596 - "Two-way RF Communication at Points of Convergence of Wire Pairs from Separate Internal Telephone Networks"

The Invention Explained

• Problem Addressed: The patent's background describes the significant expense and complexity of providing services like cable television to residences, particularly apartment and office buildings, which traditionally required installing new, dedicated coaxial cabling throughout the structure ('596 Patent, col. 1:12–34).
• The Patented Solution: The invention proposes using the building's pre-existing telephone wiring (twisted pairs) to carry high-frequency radio frequency (RF) signals, such as video or data, simultaneously with low-frequency voice signals ('596 Patent, Abstract). A central "transceiver/switch" is placed at a "point of convergence" where telephone lines from multiple units come together (e.g., a wiring closet), which selects and injects the RF signals onto the lines running to individual apartments or offices, thereby avoiding the need to run new wires to each television or computer ('596 Patent, col. 8:6–25; Fig. 1a).
• Technical Importance: This approach enabled the delivery of new broadband services by leveraging the ubiquitous telephone infrastructure already present in nearly every building, potentially reducing deployment costs and complexity ('596 Patent, col. 3:41–52).

Key Claims at a Glance

• The complaint asserts infringement of "one or more claims" without specifying which ones (Compl. ¶138). Independent claim 1 is representative of the system claimed.
• Essential elements of independent claim 1 include:
  • An "interface" coupled to a source of a video signal, two-wire telephone lines serving individual units, and a telephone exchange.
  • Circuitry for receiving the video signal from the source.
  • Circuitry for transmitting the video signal onto at least one telephone line in a frequency range different from that used for voice signals.
  • Circuitry for concurrently passing voice signals between the telephone lines and the telephone exchange.
  • Functionality to prevent the transmitted video signal from being sent to the telephone exchange.
• The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 6,243,446 - "Distributed Splitter for Data Transmission Over Twisted Wire Pairs"

The Invention Explained

• Problem Addressed: As a continuation of the application leading to the ’596 Patent, this patent addresses the same technical challenge of using existing telephone lines to deliver broadband services without installing new cabling (’446 Patent, col. 1:14–36).
• The Patented Solution: The '446 patent claims a method for providing video signal communication that mirrors the system of the ’596 Patent. The method involves receiving a video signal at a central interface, transmitting it over telephone lines at frequencies separate from voice signals, and concurrently passing the voice signals between the subscriber and the telephone exchange, while preventing the video signal from entering the public telephone network (’446 Patent, Abstract; col. 28:22–49).
• Technical Importance: This patent protects the method of operating the system described in the parent ’596 Patent, broadening the scope of protection for the core technological contribution.

Key Claims at a Glance

• The complaint asserts infringement of "one or more claims" without specification (Compl. ¶149). Independent method claim 1 is representative.
• Essential elements of independent claim 1 include:
  • Receiving a video signal from a source at an interface.
  • Transmitting the video signal onto a telephone line in a frequency range different from voice signals.
  • Concurrently passing voice signals between the telephone line and a telephone exchange.
  • Preventing the transmission of the video signal to the telephone exchange.
• The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 6,542,585 - "Distributed Splitter for Data Transmission Over Twisted Wire Pairs"

• Technology Synopsis: As another continuation in the same patent family, the '585 patent claims a communication system for transmitting information over a telephone wiring network. The system uses a signal interface at a point of convergence to receive an external signal and transmit a corresponding internal signal in a high-frequency band over the existing telephone wiring to a transceiver at the destination, while voice signals continue to operate in their normal, lower-frequency band ('585 Patent, Abstract).
• Asserted Claims: The complaint asserts "one or more claims" without specification (Compl. ¶160). Independent claims 1 and 6 are asserted.
• Accused Features: The accused features are the components and operation of the CenturyLink DSL service, which delivers high-speed data over telephone lines using a DSLAM and customer-premises equipment like DSL modems and filters (Compl. ¶¶130–133, 160).

III. The Accused Instrumentality

Product Identification

• The "CenturyLink DSL" service and associated hardware (Compl. ¶130).

Functionality and Market Context

• The complaint alleges the accused instrumentality is a Digital Subscriber Line (DSL) system that provides high-speed internet to residential and business customers (Compl. ¶130). The system functions by using a Digital Subscriber Line Access Multiplexer (DSLAM) located at a telephone company's central office or a remote terminal (Compl. ¶131). The DSLAM receives data signals from an internet service provider and transmits them as high-frequency signals over the pre-existing telephone wire network to a customer's premises (Compl. ¶131). Customers are provided with self-installation kits that include a transceiver (DSL modem or router) and low-pass filters, which are plugged into telephone jacks to separate the high-frequency data signals from the low-frequency voice telephone signals and prevent interference (Compl. ¶¶132–133). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

'596 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
An interface coupled to ... two-wire telephone lines, ... and a telephone exchange	The DSLAM, located at a central office or remote terminal, serves as the interface connected to the public telephone exchange and the telephone lines that run to customer premises.	¶131	col. 8:10-14
circuitry for receiving said video signal from said source	The DSLAM includes circuitry for receiving data signals from an external source, such as an internet service provider.	¶131	col. 8:16-25
circuitry for transmitting said received video signal onto at least one of said telephone lines in a selected frequency range that is different from frequencies at which said voice signals are carried	The DSLAM transmits high-frequency data signals over the telephone wiring network, operating in a frequency band above the voiceband used for telephone service.	¶131	col. 3:59-65
to cause said video signal to be coupled to a receiver connected to said telephone line at the unit served by said line	The high-frequency data signals are transmitted to a receiver (a DSL modem or router) located at the customer's residence or business.	¶131, ¶133	col. 4:5-9
circuitry for concurrently passing said voice signals between said telephone lines and said telephone exchange	The system operates over active telephone lines, and the provided low-pass filters separate voice signals from data signals, allowing for concurrent use.	¶133	col. 9:21-25
and preventing transmission of said received video signal to said telephone exchange	DSL architecture requires a splitter, typically integrated into the DSLAM, that blocks the high-frequency data signals from entering the public switched telephone network.	¶131	col. 15:10-14

Identified Points of Contention

• Scope Questions: A central issue may be whether the term "video signal," used throughout the patent claims and described in the context of cable TV, can be construed to read on the "data signals" of the accused DSL internet service. Another question is whether the claimed "interface" at a "point of convergence," often depicted in the specification as a wiring closet within a subscriber's building, can be construed to cover a DSLAM located at a telephone company's central office or remote terminal.
• Technical Questions: The complaint alleges a "distributed filtering system" where users plug in low-pass filters at individual telephone jacks. A question arises as to whether this customer-implemented filtering satisfies the claim limitation of "preventing transmission of said received video signal to said telephone exchange," which the patent specification may suggest is a function performed by the central "interface" itself.

V. Key Claim Terms for Construction

The Term: "video signal"

• Context and Importance: This term's construction is critical to the infringement analysis. The accused product is a general-purpose internet data service, while the patent's background and embodiments are heavily focused on the distribution of cable television signals. The outcome of the case may depend on whether this term is interpreted broadly to mean any wideband data or narrowly to mean conventional television signals.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification states that the disclosed systems are designed to transmit "telephone signals and non-telephonic signals (such as cable television signals, other video signals, audio signals, data signals, and control signals)" ('596 Patent, col. 2:56-60). This language suggests "video signal" is an exemplary, not exclusive, type of non-telephonic signal.
  • Evidence for a Narrower Interpretation: The "Background of the Invention" section exclusively discusses the challenges of providing "cable TV signals" and "video on demand" ('596 Patent, col. 1:12–col. 3:4). The abstract and numerous embodiments consistently refer to televisions, VCRs, and video cameras as the destination and source devices.

The Term: "interface"

• Context and Importance: The physical location of the claimed "interface" relative to the subscriber is a potential point of dispute. Practitioners may focus on this term because the patent's solution is framed as solving the problem of installing new wiring within a building, suggesting a proximate location, whereas the accused DSLAM is located remotely at a telephone company facility.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The claims use the general term "interface." The specification notes that for houses, the "point of common access can be a telephone pole," which is outside the residence ('596 Patent, col. 1:35-36).
  • Evidence for a Narrower Interpretation: The specification describes the problem as installing "coaxial cable leading through the entire building" and providing service "within the unit" ('596 Patent, col. 1:21-29). The patent figures consistently show the "transceiver/switch" (the interface) located between the external telephone trunk line and the "local networks" inside individual residences or offices ('596 Patent, Fig. 1a).

VI. Other Allegations

Indirect Infringement

• The complaint alleges both induced and contributory infringement (Compl. ¶¶138, 149, 160). Inducement is alleged based on Defendants' sales of CenturyLink DSL to customers and provision of self-installation kits with instruction manuals, which allegedly instruct users to configure and use the system in an infringing manner (Compl. ¶¶133, 141, 152, 163). Contributory infringement is alleged on the basis that CenturyLink DSL is a material part of the claimed invention, was known to be adapted for an infringing use, and is not a staple article of commerce suitable for substantial non-infringing use (Compl. ¶¶142, 153, 164).

Willful Infringement

• The complaint alleges that infringement has been willful and intentional (Compl. ¶¶143, 154, 165). The basis for this allegation includes claims of providing "actual notice" of the alleged infringement of the patents-in-suit to certain Qwest entities, which were subsequently acquired by CenturyLink (Compl. ¶¶137, 148, 159).

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

• A core issue will be one of definitional scope: can the term "video signal," which is rooted in the patent’s description of cable television distribution, be construed to cover the general-purpose "data signals" transmitted by the accused DSL internet service? The answer may determine whether the accused product falls within the patent's claims at all.
• A second key issue will be one of architectural scope: does the claimed "interface," described in the patent as a solution to in-building wiring problems and often depicted in wiring closets, read on the accused system's DSLAM, which is located remotely at a telephone company's central office or terminal? This question addresses a fundamental potential mismatch between the patented system architecture and that of the accused DSL technology.
• A central procedural question will be the impact of prior litigation: how will the claim constructions from the EarthLink case, which the complaint notes was previously litigated in the same court, affect the present dispute under the doctrine of issue preclusion (collateral estoppel)?