Expired, full termArchiveSolo inventor
Improvement in electric speaking-telephones
US 213,090 A
Overview
The published document from the USPTO: abstract, claims, description and drawings. Open it full size
Read the whole patent
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
Sources & verification
Official USPTO records
Cross-check elsewhere
Everything on this page comes from the USPTO record linked above.