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Automatic telephone system

US 1,461,980 A · Inventors: NELSON MARTIN L

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Listed from its USPTO record in Patent Yard's full-term archive. Its claims, description and drawings are in the USPTO PDF and on Google Patents, and the Claude kit works from them.

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Why it's free to use

  • Granted July 17, 1923. A patent granted before 1976 lasted at most 17 years from grant, so its term ended by July 17, 1940.
  • We check US rights only. Old patents can still inspire new ones: improvements may be patentable.
FiledJune 30, 1919
GrantedJuly 17, 1923
Term endedJuly 17, 1940
Application number—
Classification (CPC)H04Q3/00
Length11 pages

Timeline

Timeline From USPTO dates

1920192319261929193219351938Application filedJune 30, 1919Patent grantedJuly 17, 1923Term endedJuly 17, 1940

Sources & verification

Official USPTO records

Full published documentText and every drawing sheet as a PDF.USPTOFile historyStatus, office actions, notices, fee records and petitions.USPTO Patent CenterPatent Public Search recordSearchable full text and bibliographic data.USPTO

Cross-check elsewhere

Google PatentsFull text, worldwide family, citing patents and legal events.patents.google.comJustia PatentsFull text, claims and classification.patents.justia.comFreePatentsOnlineFull text and PDF.freepatentsonline.comEspacenetForeign family and legal status.European Patent Office

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