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Expired European patentEurope

Tone detection process and device for implementing said process

EP 0243561 B1 · Applicant: International Business Machines Corporation

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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 April 30, 1986 and granted April 10, 1991. A European patent lasts at most 20 years from filing, so its term ended April 30, 2006.
  • 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 October 30, 2011.
  • 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.
FiledApril 30, 1986
PublishedNovember 4, 1987
GrantedApril 10, 1991
Term endedApril 30, 2006
Application numberEP 86430013
Classification (CPC)H04Q1/457

Timeline

Timeline From EPO dates

1987198919911993199519971999200120032005Application filedApril 30, 1986PublishedNov 4, 1987Patent grantedApril 10, 1991Term endedApril 30, 2006

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

Everything on this page comes from the EPO record linked above. EPO data used under CC BY 4.0.