Tell about invention of Telephone ?

After some negotiation, the investors allowed for Bell to work on both technologies, with more focus on the popular harmonic telegraph.

Alexander Graham Bell, one year younger than Lars Magnus Ericsson, had been born in Edinburgh. Bell’s interest in telephony came through his mother, who was deaf, and his father, Alexander Melville Bell, who was a teacher of elocution, famous for the phonetic transcription system he had developed to help the deaf learn to speak (and which he described in a book entitled Visible Speech).

However, in the end, the telephone won out.

While a professor at New York University in 1835, Samuel Morse proved that signals could be transmitted by wire. He used pulses of current to deflect an electromagnet, which moved a marker to produce written codes on a strip of paper inventing Morse Code. A public demonstration followed in 1838, and in 1843 the United States Congress funded $30,000 to construct an experimental telegraph line from Washington to Baltimore. His first telegraph message became world famous, and ushered in an era of nearly instantaneous communication.

As Bell would later explain, “If I could make a current of electricity vary in intensity precisely as the air varies in density during the production of sound, I should be able to transmit speech telegraphically.”

The Bell family migrated to Canada in 1870; two years later Alexander Melville Bell was offered a teaching post at a school for the deaf in Boston in the United States, but he successfully recommended his son for the post instead.

Although highly successful, the telegraph was limited to receiving and sending one message at a time. Bell theorized about the possibility of transmitting multiple messages over the same wire at the same time. His "harmonic telegraph" was based on the principle that several notes could be sent simultaneously along the same wire if the notes or signals differed in pitch.

During the 1870's, two well known inventors both independently designed devices that could transmit sound along electrical cables. Those inventors were Alexander Graham Bell and Elisha Gray. Both devices were registered at the patent office within hours of each other.

On March 7, 1876, Bell was awarded a patent on the device, and three days later, he made his first successful telephone call to his assistant, electrician Thomas Watson, who would hear Bell’s famous words transmitted through the wire: “Mr. Watson, come here. I want you.”

There followed a bitter legal battle over the invention of the telephone, which Bell subsequently won.

Another inventor, Ohio born Elisha Gray, invented a device similar to the telephone while working on his own solutions to improve the telegraph.

Father and son were at this time working together to try to discover whether sound could be made visible for the deaf with the help of telegraphy.
But many others had already been pursuing the idea of telephony for years. A resolution of the US House of Representatives in June 2002 claimed that Bell had nefariously acquired and exploited an apparatus, the “teletrophono”, invented by Antonio Meucci long before Bell and Gray.

Soon after establishing the Bell Telephone Company in 1877, Bell found himself in what would become an almost 20-year legal battle with other inventors who claimed they had invented the telephone before or around the same time as Bell, his most notable rival being Elisha Grey. However, in the end, none of the lawsuits proved successful.

One damaging piece of evidence for Bell was that Meucci’s material had disappeared without trace from the very laboratory at which Bell was carrying out his experiments.

The day Alexander Graham Bell filed his patent for the telephone, February 14, 1876, Gray's attorney filed a Patent Caveat, which would give him 90 days to file an additional patent application. The caveat would prevent anyone else that filed an application on the same or similar invention from having their application processed for ninety days.

The telegraph and telephone are very similar in concept, and it was through Bell's attempts to improve the telegraph that he found success with the telephone.

The telephone proved wildly successful, and within 10 years, more than 100,000 people in the United States owned telephones.

In the 1880s, proceedings initiated by the American government charged Bell with “fraudulent and dishonest conduct” and claimed that his patent should be revoked. These proceeding were discontinued after Meucci’s death in 1889 and the expiry of Bell’s patent in 1893.

The telegraph had been a highly successful communication system for about 30 years before Bell began experimenting. The main problem with the telegraph was that it used Morse code, and was limited to sending and receiving one message at a time.

But because Bell's patent (received 5th in line on February 14) arrived before Gray's patent caveat (received 30th in line), the United States Patent Office decided not to hear the caveat and awarded Bell the patent, #174465. Gray would start a lawsuit against Bell in 1878, which he would ultimately lose.

But a few years after founding Bell Telephone Company, Bell quickly lost interest in managing the business aspect of his enterprise and sold his shares.

Bell had a good understanding about the nature of sound and music. This enabled him to perceive the possibility of transmitting more than one message along the same wire at one time. Bell's idea was not new, others before him had envisaged a multiple telegraph.

A later investigation, published by A. Edward Evenson in 2000, claims that Bell’s attorneys acquired technical details from Gray’s attorneys (both had lawyers acting as their agents) that are said to have been added to Bell’s patent after it had been submitted. The whole saga has elements reminiscent of a thriller.

In 1880 he invested his sizable fortune into building a new scientific experimental facility called the Volta Laboratory,

The telephone was a large part of modern life in the 20th Century, and still continues a prominent place in society today.