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Improvement in electric speaking-telephones

US 213,090 A

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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.

Why it's free to use

  • Granted March 11, 1879. A patent granted before 1976 lasted at most 17 years from grant, so its term ended by March 11, 1896.
  • We check US rights only. Old patents can still inspire new ones: improvements may be patentable.
FiledJanuary 16, 1879
GrantedMarch 11, 1879
Term endedMarch 11, 1896
Application number—
Classification (CPC)H04M9/001
Length5 pages

Timeline

Timeline From USPTO dates

188018821884188618881890189218941896Application filedJan 16, 1879Patent grantedMarch 11, 1879Term endedMarch 11, 1896

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