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Expired European patentEurope

Circuit for the processing, transmission and acoustic reproduction of digitalized tone frequency signals

EP 0082905 B1 · Applicant: ITT INDUSTRIES INC.

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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 December 24, 1981 and granted April 9, 1986. A European patent lasts at most 20 years from filing, so its term ended December 24, 2001.
  • 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 June 24, 2007.
  • 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.
FiledDecember 24, 1981
PublishedJuly 6, 1983
GrantedApril 9, 1986
Term endedDecember 24, 2001
Application numberEP 81710059
Classification (CPC)H04R5/02 +2 more

Timeline

Timeline From EPO dates

1982198419861988199019921994199619982000Application filedDec 24, 1981PublishedJuly 6, 1983Patent grantedApril 9, 1986Term endedDec 24, 2001

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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