Brightsky LLC v. Plover Bay Tech Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: BrightSky LLC dba Simplifi (Florida)
  • Defendant: Plover Bay Technologies Ltd. (Cayman Islands) and Peplink International Ltd. (Hong Kong)
  • Plaintiff's Counsel: Gardella Alciati P.A.
• Case Identification: 9:25-cv-80704, S.D. Fla., 04/13/2026
• Venue Allegations: Venue is asserted as proper because the defendants are foreign corporations.
• Core Dispute: Plaintiff alleges that Defendants' POTS Adapter, which connects legacy telephone equipment to modern cellular networks, infringes a patent related to technology for interfacing analog telephone systems with Voice-over-LTE (VoLTE) networks.
• Technical Context: The technology addresses the market need created by the phasing out of traditional analog Plain Old Telephone Service (POTS) lines, enabling businesses to continue using existing equipment like alarm systems, fax machines, and elevator phones over modern cellular infrastructure.
• 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
2019-01-01	Plaintiff Simplifi begins operations
2021-09-02	U.S. Patent No. 11,974,173 Priority Date
2024-04-30	U.S. Patent No. 11,974,173 Issue Date
2026-04-13	Complaint Filing Date

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

• Patent Identification: U.S. Patent No. 11,974,173, Wired Telephone to VoLTE [Voice over LTE] Adapter, issued April 30, 2024.

The Invention Explained

• Problem Addressed: The patent's background section describes the problem that arises as public utility companies discontinue traditional Plain Old Telephone Service (POTS), leaving facilities with existing internal telephone infrastructure (e.g., for alarm systems, elevators, fax machines) unable to connect to external networks U.S. Patent No. 11,974,173, col. 1:11-26 Prior cellular communication systems were often unable to reliably support the data signaling used by such legacy analog devices U.S. Patent No. 11,974,173, col. 3:1-14
• The Patented Solution: The invention is an adapter that serves as an interface between the legacy internal POTS wiring and a modern LTE cellular network U.S. Patent No. 11,974,173, col. 1:40-46 As depicted in Figure 1, the adapter includes a Subscriber Line Interface Circuit (SLIC) to connect to the analog telephone device and a microcontroller that processes the signals, which are then passed to an LTE cellular modem for transmission over a VoLTE network U.S. Patent No. 11,974,173, FIG. 1 This allows the legacy equipment to function over the modern network by providing the necessary electrical signaling, tone processing, and signal conversion U.S. Patent No. 11,974,173, abstract
• Technical Importance: The patented solution enables the continued use of installed legacy POTS-based equipment, obviating the expense of replacing or upgrading devices like security panels, POS terminals, and elevator call boxes that rely on analog line characteristics U.S. Patent No. 11,974,173, col. 2:57-64

Key Claims at a Glance

• The complaint asserts infringement of at least independent claim 1 Compl. ¶19
• The essential elements of independent claim 1 include:
  • A radio communications device supporting 4G/5G LTE cellular communications.
  • A data interface configured to exchange modem control commands and audio data with an LTE cellular modem.
  • A telephone interface configured to provide a two-wire analog telephone interface for connection to a telephone device.
  • A controller configured to perform a series of specific functions: exchanging control signals with the telephone device, exchanging analog voice signals, converting between analog signals and a Pulse Code Modulation (PCM) data stream, exchanging control information with the LTE modem to manage a cellular session, and exchanging the PCM data stream via the LTE cellular session.
• The complaint expressly reserves the right to assert additional claims based on discovery Compl. ¶36

III. The Accused Instrumentality

Product Identification

• The Peplink POTS Adaptor Compl. ¶19

Functionality and Market Context

• The complaint alleges the Accused POTS Product is an adapter designed to connect legacy analog phone lines and equipment to a modern LTE cellular network Compl. ¶23
• Promotional materials cited in the complaint state the product's primary benefit is to "Easily Convert your Plain Old Telephone System (POTS) connections to LTE Cellular" Compl. ¶23 The complaint includes a screenshot from Defendants' website showing the POTS Adapter, which advertises its ability to convert a "hard-to-maintain Plain Old Telephone System to cost-effective VoLTE infrastructure" Compl. ¶19 The product is allegedly marketed for use with alarm systems, elevators, and other legacy applications Compl. ¶23
• The complaint alleges that Defendants copied the technology after Plaintiff's commercial success and introduced a "foreign-manufactured version" at a lower price Compl. ¶20

IV. Analysis of Infringement Allegations

Claim Chart Summary

11,974,173 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A radio communications device supporting 4G/5G Long Term Evolution (LTE) cellular communications...	The Accused POTS Product is a device that enables the connection of a POTS line to an LTE cellular connection.	¶23	col. 1:40-42
a data interface configured to exchange modem control commands and audio data with an LTE cellular modem;	The product is configured to provide an interface between a POTS line and an LTE cellular modem, handling both control commands and audio data.	¶24	col. 5:18-24
a telephone interface configured to provide a two-wire analog telephone interface for connection to a telephone device;	The product includes an RJ11 jack to provide a connection to an analog phone device with a two-wire plug. The complaint includes a product image showing two RJ11 ports labeled "Phone" Compl. p. 9	¶25	col. 3:20-28
a controller configured to: exchange control signals via the telephone interface to manage voice call operations with the telephone device;	The product is configured to support phone calls from a traditional POTS phone, which requires exchanging control signals to manage voice call operations.	¶26	col. 6:49-55
exchange analog voice channel signals corresponding to digitally modulated voice channel signals exchanged with the telephone device via the telephone interface;	The product supports calls from a POTS phone over an LTE modem, requiring conversion of analog voice signals from the phone to corresponding digital signals for the modem.	¶27	col. 3:47-54
convert signals between the analog voice channel signals and a Pulse Code Modulation (PCM) voice channel data stream;	The product allegedly includes a Si32184 SLIC (Subscriber Line Interface Controller) chip that converts analog POTS signals to the digital domain via PCM. The complaint provides a photograph of the accused product's circuit board showing this chip Compl. p. 11	¶28	col. 3:52-57
exchange control information with the LTE cellular modem via the data interface to establish and manage an LTE cellular session; and	The product provides an interface between a POTS telephone and an LTE modem that handles control information to create, maintain, and terminate a connection.	¶29	col. 5:45-50
exchange the Pulse Code Modulation (PCM) voice channel data stream via the LTE cellular session via the LTE cellular modem.	The product allegedly uses a SLIC with a PCM module to convert analog signals to the digital domain for transmission by the LTE modem.	¶30	col. 5:57-65

Identified Points of Contention

• Scope Questions: A potential issue may be the scope of the term "telephone device." The complaint and patent contemplate its use with equipment such as "fire alarm control panels," "security system alarm panels," and "fax machines" Compl. ¶27 '173 Patent, col. 2:57-61 The definition of "telephone device" and whether all such enumerated systems fall within its scope could become a point of contention.
• Technical Questions: The infringement allegation for the "controller" limitation relies on identifying multiple components, including a Si32184 SLIC chip, that allegedly work together to perform the claimed functions Compl. ¶28 A key technical question will be whether the combination of components in the Accused POTS Product actually performs all of the discrete functions recited in the claim for the "controller," such as the specific conversion to a PCM data stream and the subsequent exchange of that stream via the LTE session.

V. Key Claim Terms for Construction

• The Term: "a controller configured to"
• Context and Importance: This term introduces the functional requirements of the invention. The infringement analysis hinges on whether the accused device's internal circuitry, which the complaint identifies as including a specific SLIC chip Compl. ¶28, performs every one of the five distinct functions recited in the sub-elements of claim 1. The construction of "controller" and what it means to be "configured to" perform these functions will be central to the dispute.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification describes the controller's functions in the context of a "microcontroller" U.S. Patent No. 11,974,173, col. 3:30-31 working in conjunction with a "Host MCU" U.S. Patent No. 11,974,173, col. 5:24-25, suggesting the "controller" may encompass multiple distributed processing components rather than a single, monolithic unit.
  • Evidence for a Narrower Interpretation: The detailed description ties the recited functions to specific components. For example, the conversion to PCM is associated with the SLIC 120, while establishing the LTE call is associated with the Host MCU 124 U.S. Patent No. 11,974,173, col. 3:52-57 U.S. Patent No. 11,974,173, col. 5:48-50 A party could argue that the claimed "controller" must be a structure that is capable of performing, or directly controls components that perform, all of the listed functions.

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced and contributory infringement, asserting Defendants encourage infringement by distributors, resellers, and end-users through promotional literature, user manuals, and technical support (Compl. ¶¶37; Compl. ¶40). The complaint also alleges the Accused POTS Product has no substantial non-infringing use Compl. ¶41
• Willful Infringement: The complaint does not contain a separate count for willful infringement. However, the prayer for relief requests a finding that the case is "exceptional" and an award of attorneys' fees Compl. p. 15, ¶(e) The inducement allegations are based on knowledge of the patent "at least as of the date of service of this Complaint" Compl. ¶39, suggesting a theory based on post-suit conduct.

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

• A core issue will be one of technical mapping: does the accused device's architecture, which allegedly uses a Si32184 SLIC chip, perform each of the five specific, sequential functions required by the "controller" limitation in Claim 1? The analysis may depend on detailed evidence of how the accused device processes and routes control signals and voice data between the analog and cellular interfaces.
• A secondary issue may be one of definitional scope: how broadly will the court construe the term "telephone device"? The case may explore whether specialized equipment like security alarm panels are properly considered "telephone devices" within the context of the patent, which could affect the scope of infringement and damages.