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Expired European patentEurope

Circuit arrangement for telecommunications exchanges, in particular telephone exchanges, with the metering impulse frequencies graduated according to time

EP 0021309 B1 · Applicant: SIEMENS AKTIENGESELLSCHAFT

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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 June 16, 1980 and granted April 13, 1983. A European patent lasts at most 20 years from filing, so its term ended June 16, 2000.
  • 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 December 16, 2005.
  • 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.
FiledJune 16, 1980
PublishedJanuary 7, 1981
GrantedApril 13, 1983
Term endedJune 16, 2000
Application numberEP 80103352
Classification (CPC)H04M3/38 +1 more

Timeline

Timeline From EPO dates

1981198319851987198919911993199519971999Application filedJune 16, 1980PublishedJan 7, 1981Patent grantedApril 13, 1983Term endedJune 16, 2000

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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