Invalidity dossier
US 7436936
Added 9/23/2026, 1:43:54 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 7,436,936 B2
Title: VoIP call through tester
Patent number: US 7,436,936 B2
Application number: US 11/064,415
Inventors: Richard D. Terpstra; Thomas S. Traylor; Gregory Keith Brown; John Thomas Ward; Andrew B. Lundgren
Assignee: Level 3 Communications LLC (original assignee Level 3 Communications LLC; an earlier assignment to LEVEL 3 COMMUNICATIONS, INC. is recorded, later assigned to LEVEL 3 COMMUNICATIONS, LLC)
Priority/filing date: 2005-02-22
Publication date: 2008-10-14
Legal status (as listed): Expired – Lifetime, expires 2026-04-12
Purpose: The patent relates to systems and methods for placing media communications through a network, and more particularly to verifying the routing of a call through a network. It addresses the problem that VoIP network providers often lack efficient means to verify that calls to a block of phone numbers are properly routed to the VoIP network, and must rely on PSTN provider assurances or manually "mine" log files and hand-draw call flows.
Plain-language scope: In described embodiments, an outbound call is generated from a test tool in a first network (e.g., a VoIP network). The outbound call includes a test key and a destination number, with the test key placed in the origination-number field. The call is routed to a second network (e.g., the PSTN) and returns to the first network as an inbound call carrying the test key and destination number. A network resource (such as a softswitch, session border controller, gateway, gateway controller, or proxy/feature server) accesses the test key and, based on it, routes the inbound call to the test tool. Embodiments also collect tracking information (e.g., SS7, IP device control, SIP including signaling latency), may calculate post-dialing delay, and may display a sequence diagram of the tracking information.
Source: https://patents.google.com/patent/US7436936/en
What the excerpt does not establish: The supplied text is explicitly marked as an excerpt with omitted text, so the full claim set and complete specification are not established here. It also does not establish the accuracy of the listed legal status or assignee data, which the source itself describes as assumptions. Claims are paraphrased from the "Definitions" summary section, not verified against the issued claims.
Generated 10/1/2026, 9:52:53 PM
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Litigation summary
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Proceedings on file (0)
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PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
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Obviousness
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Extensions
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Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.