# Alexander Graham Bell's Patent for the Telephone

> Alexander Graham Bell's 1876 patent describing the method and apparatus for transmitting vocal sounds telegraphically, effectively inventing the telephone.

- **Patent:** US 174465
- **Original title:** Improvement in telegraphy
- **Owner:** Individual
- **Granted:** 1876
- **Status:** Public domain (expired)
- **Times cited:** 9
- **Field:** telecommunications

## What it does

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 it does NOT cover

- 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

## The clever bit

Bell realized that instead of using intermittent electrical pulses like a telegraph, he needed to create a continuous, undulating current that mimicked the actual waveform of the human voice.

## Real-world examples

1. Early liquid transmitters
2. Magnetic telephone receivers
3. The first experimental telephones

## Why it matters

This is widely considered one of the most valuable patents in history, as it provided the legal foundation for the birth of the telecommunications industry. It sparked intense legal battles over priority of invention, most notably against Elisha Gray, and established the framework for the Bell Telephone Company.

## Frequently asked questions

### What does Alexander Graham Bell's Patent for the Telephone cover?

Alexander Graham Bell's 1876 patent describing the method and apparatus for transmitting vocal sounds telegraphically, effectively inventing the telephone.

### Who owns patent US 174465?

Individual owns this patent, granted in 1876.

### When does this patent expire?

This patent has expired and is now in the public domain — anyone can use the invention freely.

### What is patent US 174465 cited by?

This patent has been cited by 9 later patents that build on its ideas.

### What problem does this patent solve?

This is widely considered one of the most valuable patents in history, as it provided the legal foundation for the birth of the telecommunications industry. It sparked intense legal battles over priority of invention, most notably against Elisha Gray, and established the framework for the Bell Telephone Company.

### What does this patent NOT cover?

Does not cover digital signal processing or packet-switched voice transmission

**Full plain-English explainer:** https://patentbrief.org/patent/us/174465/bell-telephone

**Original patent:** https://patents.google.com/patent/US174465

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


## Related patents

Semantically similar inventions in the PatentBrief corpus:

- [How Samuel Morse Patented the Electric Telegraph System](https://patentbrief.org/patent/us/1647/morse-telegraph) — Samuel Morse's 1840 patent for the electric telegraph, which enabled long-distance communication by sending electrical pulses over wires to represent letters.
- [How Marconi Patented Early Wireless Telegraphy Signals](https://patentbrief.org/patent/us/586193/radio-wireless-marconi) — Guglielmo Marconi's 1897 patent for sending electrical signals through the air to enable early wireless communication.
- [Edison's First Patent: An Electric Vote Recorder](https://patentbrief.org/patent/us/90646/edison-first-patent-vote-recorder) — Thomas Edison's very first patent, granted in 1869, describes an early machine designed to use electricity to quickly record and tally votes, primarily for legislative bodies.
- [How Thomas Edison Improved Early Phonograph Recording](https://patentbrief.org/patent/us/200521/phonograph-edison) — An 1878 patent by Thomas Edison detailing mechanical improvements to early sound recording devices to make them more reliable.
- [Lee De Forest's Early Radio Telegraphy System](https://patentbrief.org/patent/us/879532/de-forest-audion-vacuum-tube) — A 1908 patent by radio pioneer Lee De Forest describing methods for transmitting and receiving wireless telegraphy signals using early vacuum tube technology.