You can freely build on Alexander Graham Bell's Patent for the Telephone
This patent expired in 1896. Every claim — 0 independent, 0 dependent — is now unenforceable. Anyone can use, reproduce, manufacture, sell, or offer for sale this technology without a license.
Original assignee
Individual
Patent granted
1876
Expired
1896
Forward citations
9
What this patent covers
The patent describes a method of transmitting vocal or other sounds telegraphically by causing electrical undulations, similar in form to the vibrations of the air accompanying the said vocal or other sounds. It utilizes a transmitter that converts sound waves into electrical currents through the movement of an armature in a magnetic field. These currents are then sent over a wire to a receiver, which converts the electrical energy back into sound waves. This process allowed for the first successful transmission of intelligible human speech over a distance.
What is now free to use
All 0 claims of US 174465 are in the public domain. Specifically:
The 0 dependent claims add narrowing limitations and are also free.
What is NOT covered
Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.
Does not cover digital signal processing or packet-switched voice transmission
Does not cover wireless or cellular radio frequency transmission
Does not cover modern fiber-optic voice communication systems
Who is building on this today
Modern telecommunications giants like AT&T, which traces its lineage directly back to the Bell Telephone Company, built the global infrastructure on the principles established here. Today, every voice-over-IP and cellular network still relies on the fundamental concept of converting sound to electrical waveforms.
Products built on expired version of this technology
Early liquid transmitters
Magnetic telephone receivers
The first experimental telephones
How to cite this patent in your documentation
Individual. US Patent 174465. Improvement in telegraphy. Granted 1876, expired 1896. Now in the public domain.
Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.
PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.