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Expired European patentEurope

Technique for adjusting signal dispersion cancellation apparatus in communications systems

EP 0488575 B1 · Applicant: AT&T Corp.

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Overview

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Listed from its EPO record in Patent Yard's archive of European patents past their term. Its claims, description and drawings are in the EPO PDF and on Google Patents, and the Claude kit works from them.

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Why it's free to use

  • Filed November 20, 1991 and granted March 26, 1997. A European patent lasts at most 20 years from filing, so its term ended November 20, 2011.
  • A supplementary protection certificate, which can extend a medicine or crop-protection patent, adds at most five and a half years, so even that would have ended by May 20, 2017.
  • We check European rights only. A US or other national patent in its family could still be in force: check its family on Espacenet or Google Patents.
FiledNovember 20, 1991
PublishedJune 3, 1992
GrantedMarch 26, 1997
Term endedNovember 20, 2011
Application numberEP 91310678
Classification (CPC)H04L25/03987 +2 more

Timeline

Timeline From EPO dates

1992199419961998200020022004200620082010Application filedNov 20, 1991PublishedJune 3, 1992Patent grantedMarch 26, 1997Term endedNov 20, 2011

Sources & verification

Official EPO records

Full published documentClaims, description and drawings as a PDF.EPOEuropean Patent RegisterProcedure, status, file inspection and legal events.EPOLinked open EP data recordThe bibliographic record this page is built from.EPO

Cross-check elsewhere

Google PatentsFull text, worldwide family, citing patents and legal events.patents.google.comEspacenetNational family members and their legal status.European Patent Office

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