The parties and the patents
The case is SIPCO LLC v. Pepperl+Fuchs SE, No. 2:26-cv-00932 (E.D. Tex.). The docket lists Judge Rodney Gilstrap and Magistrate Judge Roy S. Payne. SIPCO is pleaded as a Georgia limited liability company based in Fairfax, Virginia, and describes itself as a research, development, and technology licensing company founded by Thomas David Petite, the named inventor on all four patents, and two business partners. Pepperl+Fuchs is alleged, on information and belief, to be a German company based in Mannheim and the successor to Pepperl+Fuchs GmbH.
The asserted patents are U.S. Patents 9,439,126, 9,860,820, 10,356,687, and 11,039,371, all titled Wireless Network Protocol System(s) and Methods. The complaint says the '126 patent issued September 6, 2016 from the national stage of a PCT application filed January 25, 2006, that the other three are a chain of continuations from it, and that all four claim priority to a provisional application filed January 25, 2005. It says the '820 and '371 patents are subject to terminal disclaimers.
Google Patents lists the '126 patent as active, with an adjusted expiration date of December 4, 2029. It lists the '820 and '687 patents as expired, with an expiration date of January 25, 2026, and the '371 patent as expired on February 5, 2026. The complaint does not state expiration dates, but its counts track that split: the '126 count alleges infringement that continues, while the counts on the other three patents are pleaded in the past tense, and the prayer seeks an injunction only as to the '126 patent.
What the complaint alleges
The accused products are Pepperl+Fuchs WirelessHART-enabled products that support wireless communication under IEC 62591, including listed Bullet WirelessHART adapters, WirelessHART gateways, a WirelessHART temperature converter, and WirelessHART adapters. The complaint alleges that under the WirelessHART mesh protocol, field devices and adapters route packets through neighboring devices to a gateway, keep lists of neighbor devices, and track successful and failed transmissions to those neighbors for use in choosing and adjusting communication paths.
There is one count per patent, each alleging direct infringement of at least claim 1, literally or under the doctrine of equivalents, plus induced and contributory infringement. The complaint recites the full text of claim 1 of each patent. In summary, claim 1 of the '126 patent covers a remote device in a network with a site controller that forwards packets from downstream devices and keeps a connection list with a success data score used to pick a path and to pick a new one when a transmission fails. Claim 1 of the '820 patent covers monitoring successful and unsuccessful transmissions and choosing a path from the connection list based on success data scores. Claim 1 of the '687 patent adds data link layer collision avoidance and error detection data and an automatic network detection protocol that registers new devices. Claim 1 of the '371 patent covers a remote device with a processor and memory that selects a path to a downstream device based on the success of attempted transmissions.
Each count also pleads that the claims are not directed to an abstract idea, describing what the complaint calls inventive components that improve wireless network operation.
The lapsed license and willfulness
The complaint alleges that Pepperl+Fuchs previously licensed SIPCO's wireless mesh portfolio, including the family the asserted patents come from, and so has had actual knowledge of the patents since at least 2017. It alleges that on July 12, 2024, SIPCO's counsel wrote to Pepperl+Fuchs identifying each patent and the accused products, noting that the prior license had lapsed, and inviting a new license; that Pepperl+Fuchs acknowledged the letter on July 17, 2024 and said it would respond by August 16, 2024 but did not; and that SIPCO wrote again on October 10, 2025.
The complaint pleads willful infringement of each patent and alleges, on information and belief, that Pepperl+Fuchs has a policy or practice of not reviewing the patents of others, including instructing its employees not to, and so has been willfully blind to SIPCO's rights. It alleges that SIPCO or its predecessors have satisfied the statutory requirements to collect pre-suit damages. For the '126 patent only, the complaint states that SIPCO does not seek damages for any accused product made, sold, offered for sale, imported, or used on or before March 1, 2022. It does not say why.
Jurisdiction, venue, and relief
Personal jurisdiction is pleaded on business in the District through distribution partners and, on information and belief, three U.S. subsidiaries registered to do business in Texas, and in the alternative under Federal Rule of Civil Procedure 4(k)(2). Venue is pleaded under 28 U.S.C. 1391(c)(3), on the ground that a foreign defendant not resident in the United States may be sued in any district.
The prayer asks for a judgment of direct and indirect infringement of each patent; a permanent injunction against infringement of the '126 patent or, in the alternative, an ongoing royalty for future infringement of the asserted patents; damages of no less than a reasonable royalty under 35 U.S.C. 284, with supplemental damages and an accounting through judgment or expiration; a willfulness finding as to each patent and treble damages; interest; and an exceptional-case finding with attorney fees under 35 U.S.C. 285. SIPCO demands a jury. Its counsel is Rozier Hardt McDonough PLLC.
What to watch next
Watch for service on Pepperl+Fuchs SE as a German company, and for its answer or a Rule 12 motion, including any challenge to jurisdiction under Rule 4(k)(2), to the willfulness and willful blindness allegations, or to patent eligibility.
Watch for whether the parties address the scope and end date of the earlier license, which the complaint describes only as lapsed.
Watch for any petition for inter partes review. The case can also end at any time, including by settlement or voluntary dismissal.