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Expired European patentEurope

Improvements in or relating to telephone circuits, monolithically integrated, for ring trip detection

EP 0143435 B1 · Applicant: SGS-THOMSON MICROELECTRONICS S.r.l.

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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 22, 1984 and granted February 20, 1991. A European patent lasts at most 20 years from filing, so its term ended November 22, 2004.
  • 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 22, 2010.
  • 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 22, 1984
PublishedJune 5, 1985
GrantedFebruary 20, 1991
Term endedNovember 22, 2004
Application numberEP 84114086
Classification (CPC)H04M19/026

Timeline

Timeline From EPO dates

1985198719891991199319951997199920012003Application filedNov 22, 1984PublishedJune 5, 1985Patent grantedFeb 20, 1991Term endedNov 22, 2004

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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