Invalidity dossier
US 5365512
Multisite trunked RF communication system with reliable control messaging network
Current assignee: MA Com Private Radio Systems Canada Corp
Added 9/23/2026, 6:12:22 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 5,365,512
Title: Multisite trunked RF communication system with reliable control messaging network
Patent number: US 5,365,512 A
Application number: US 08/084,944
Inventors: Edward A. Combs; Dennis M. Maddox; Wim A. Imron
Original assignee: Ericsson GE Mobile Communications Inc.
Current assignee (as listed): MA Com Private Radio Systems Canada Corp; MA Com Private Radio Systems Inc. (listing may be inaccurate)
Priority/filing date: 1993-07-02
Publication (grant) date: 1994-11-15
Legal status: Expired - Fee Related; anticipated expiration 2013-07-02
Purpose and scope (plain language): The patent relates to a multisite switch that coordinates trunked radio frequency (RF) communications between multiple sites, and more particularly to providing plural control message buses so switch operation is redundant and reliable. Trunked RF repeater systems let many users share a limited number of RF channels. A "multisite switch" establishes control and audio signal pathways between repeaters of different sites at the start of each call and takes them down at the end. The switch receives a channel assignment from a primary site controller, assigns an internal audio slot, sends channel requests over the control messaging bus to secondary site controllers, and later propagates "channel drop" commands to release working channels and break audio pathways. The switch also supports land-line telephone subscribers (via a central telephone interconnect switch) and dispatch consoles.
Source: https://patents.google.com/patent/US5365512/en
What the excerpt does not establish: It does not provide the full claims, the complete detailed description, the drawing contents, or the specific prior-art references. It gives no details on bus arbitration, message formats, or the exact redundancy mechanism. It does not establish litigation, ownership-transfer validity, or patent validity. The listed current assignees and legal status are expressly stated to be assumptions, not legal conclusions. Several abbreviations in the source (e.g., "CIS") appear inconsistent with "CTIS" and are not clarified here.
Generated 10/1/2026, 9:42:57 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.