Invalidity dossier
US 4701845
User interface processor for computer network with maintenance and programmable interrupt capability
Current assignee: Unisys Corp
Added 9/21/2026, 10:39:41 AM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
US4701845 — Patent Overview
Title: User interface processor for computer network with maintenance and programmable interrupt capability
Patent number: US4701845A
Application number: US06/664,896
Inventors: David A. Andreasen; Jerrold E. Buggert; Harshad K. Desai; Zubair Hussain
Original assignee: Unisys Corp (later listed as current assignee). Burroughs Corporation appears in 1985 assignment records; a 1988 reassignment to Unisys Corporation (via merger) is noted.
Priority date: 1984-10-25 | Filing date: 1984-10-25 | Publication/grant date: 1987-10-20
Legal status (as listed): Expired – Fee Related; anticipated expiration 2004-10-25. Google notes legal status is an assumption, not a legal conclusion.
Plain-language purpose and scope: The disclosure describes a specialized maintenance processor called the User Interface Processor (UIP) for a computer network. The UIP interfaces a central host processing unit to network elements—data link processors connecting remote peripherals, an operator display terminal, external cabinets, and a power control card enabling connection to a remote support center for diagnostic and fault-location services. It connects to the host via a processor interface card and to peripherals/terminals via a data link interface/host dependent port controller. Serial communication controllers and communication I/O units work with timers and a priority interrupt controller for host communication in both normal operation and maintenance/diagnostic service. Each network element, when initiated, runs self-test routines and reports results to the UIP; self-test data may be transported to a remote diagnostic unit. Many networks at different locations may connect to one remote support center on a time-shared basis. The drawings include FIG. 1 (two sheets, FIG. 1-1 and FIG. 1-2) and FIGS. 1A–1D as system/network drawings.
What the excerpt does not establish: It does not provide the full claim text, detailed embodiments, or the complete description. It does not establish validity, infringement, litigation history, or the content of cited prior art beyond listed patent numbers. The excerpt omits much of the specification and all claims.
Generated 10/1/2026, 10:01:23 PM
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Litigation summary
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Proceedings on file (0)
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No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
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
Earlier patents, publications, and products that may anticipate or render the claims unpatentable.
Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.