The
History of Communication Technology
Telephone
The
History of Communication
has certainly changed a lot over the past 150 years. When our founding fathers
first came to America, the only form of communication they had with one another
was through letters, which could take days or even weeks to reach its
destination.
Sending letters to England could take months. But even before that
Native Americans actually used smoke signals to communicate with one another.
Native Americans are not the only group of people who have used smoke signals
to communicate. The Chinese have also used smoke signals as well as the Boy
Scouts of America. This form of communication is used by creating puffs of
smoke using a fire and a blanket. The smoke signals must be used in an area
where they will be visible to the receiver and is usually transmitted on top of
a hill or mountain .
It
was evident that something had to be developed to make communicating with one
another easier and faster. That’s where the telephone comes in. It could
actually be considered the greatest invention of the nineteenth century. It not
only made communicating with others who were miles away much quicker, it also
spawned the growth of many businesses since it made communication much easier.
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Some
of the first telephones
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Surprisingly,
there were two people in the running to patent the telephone, not just one
person as the majority of people believe. In the 1870s, two relatively unheard
of inventors of this time, Alexander Graham Bell and the less known Elisha
Gary, both independently designed devices that could transmit speech
electrically. This would later be known as the telephone, of course.
Both men
rushed their respective designs to the patent office within hours of each
other, but Bell patented his telephone first. Elisha Gray and Alexander Graham
Bell entered into a famous legal battle over the invention of the telephone,
which as most people know, Bell won.
The
definition of the telephone is, “An instrument which converts sound,
specifically the human voice, to electrical impulses of various frequencies and
then back to a tone that sounds like the original voice.
The
telephone was actually discovered by Bell accidentally in his attempts to
improve the telegraph. The telegraph was a highly successful system with its
dot-and-dash Morse code, but it was basically limited to receiving and sending
one message at a time. Bell's extensive knowledge of the nature of sound and
his understanding of music enabled him to conjecture the possibility of
transmitting multiple messages over the same wire at the same time.
Although
the idea of a multiple telegraph had been in existence for some time, Bell
offered his own harmonic approach as a possible practical solution. 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.
Cellular phones are one of the fastest growing and most demanding telecommunications applications. Today, it represents a continuously increasing percentage of all new telephone subscriptions around the world. Currently there are more than 45 million cellular subscribers worldwide, and nearly 50 percent of those subscribers are located in the United States. It is predicted that cellular systems using a digital technology will become the universal method of telecommunications. By the year 2005, forecasters predicted that there would be more than 100 million cellular subscribers worldwide. Cell phones are more common today than landlines. It is impossible to go out to the grocery store or to a restaurant and not see someone on a cell phone.
Today's
modern cellular phones
Even before cell phones, however, there was something called a satellite phone. Satellite phones were very similar to cell phones in that they could be used almost anywhere, but satellite phones weren’t transmitted by towers they were transmitted by satellites orbiting the earth. Originally the Iridium satellite constellation consisted of 77 active satellites that orbited the earth from pole to pole.
The name Iridium came from the element iridium which has the
atomic number of 77. Today the Iridium satellite constellation consists of a
system of 66 activate satellites in low earth orbit at a height of 485 miles.
The Iridium satellites traveling at 17,000 miles an hour will orbit from pole
to pole in 100 minutes. Unlike the Globalstar constellation the Iridium
constellation communicate with each other using inter satellite links. This
allows for the total planetary coverage only Iridium can offer. Each satellite
had four inter satellite links two to communicate with satellites on either side
and tow to communicate to other satellites for and aft in the same orbital
plane.
Satellite
phones
The LM700 satellite was first used in the Iridium system. The system used L-Band to provide the global communications. The Iridium system employs L-Band FDMA / TDMA signal at 4.8 kbps for voice and 2400 bps for data. 125 spacecraft built by Lockheed were used to place the satellites in orbit at a cost of $700M. The spacecraft is three-axis stabilized using a hydrazine propulsion system. The spacecraft has two solar panels with 1-axis articulation. Each satellite uses 48 spot beams arranged as 16 beams in three sectors for earth coverage and uses Ka-Band for cross links and ground commanding.
The original design of the Iridium satellite was of the a completely static 1960s type design with control and time-triggered messages for an entire orbit that would be uploaded each time the satellite passed the poles. When it was found this design did not offer enough bandwidth to upload each satellite quickly over the poles this design was dropped in favor of a performed dynamic control of routing and channel selection which delayed the delivery of the system by one year.
The telephone came a long way since it was first developed in the late 1800s. There have been many changes to this form of communication and as of now, it seems like nothing is impossible. From satellite phone to cell phones to smart phones, it seems like mobile communication has just started to take off. Don’t be surprised if within the next 20 years more people have cell phones than house phones!
The telephone - important dates
1. 1874 - Principal of the telephone was uncovered.
2. 1876 - Alexander Graham Bell invents the telephone, beating Elisha Gray by a matter of hours.
3. 1877 - The very first permanent outdoor telephone wire was completed. It stretched a distance of just three miles. This was closely followed in the U.S. by the worlds first commercial telephone service.
4. 1878 - The workable exchange was developed, which enabled calls to be switched between subscribers rather than having direct lines.
5. 1879 - Subscribers began to be designated by numbers and not their names.
6. 1880's - Long distance service expanded throughout this period using metallic circuits.
7. 1888 - Common battery system developed by Hammond V. Hayes, allows one central battery to power all telephones on an exchange, rather than relying on each units own battery.
8. 1891 - First automatic dialling system invented by a Kansas City undertaker. He believed that crooked operators were sending his potential customers elsewhere. It was his aim to get rid of the operators altogether.
9. 1900 - First coin operated telephone installed in Hartford, Connecticut.
10. 1904 - "French Phone" developed by the Bell Company. This had the transmitter and receiver in a simple handset.
11. 1911 - American Telephone and Telegraph (AT & T) acquire the Western Union Telegraph Company in a hostile takeover. They purchased stocks in the company covertly and the two eventually merged.
12. 1918 - It was estimated that approximately ten million Bell system telephones were in service throughout the U.S.
13. 1921 - The switching of large numbers of calls was made possible through the use of phantom circuits. This allowed three conversations to take place on two pairs of wires.
14. 1927 - First transatlantic service from New York to London became operational. The signal was transmitted by radio waves.
15. 1936 - Research into electronic telephone exchanges began and was eventually perfected in the 1960's with the electronic switching system (SES).
16. 1946 - Worlds first commercial mobile phone service put into operation. It could link moving vehicles to a telephone network via radio waves.
17. 1947 - Microwave radio technology used for the first time for long distance phone calls.
18. 1947 - The transistor was invented at Bell laboratories.
19. 1955 - Saw the beginning of the laying of transatlantic telephone cables.
20. 1962 - The worlds first international communications satellite, Telstar was launched.
21. 1980's - The development of fiber optic cables during this decade, offered the potential to carry much larger volumes of calls than satellite or microwaves.
22. 1980's, 1990's, to present - Huge advances in micro electronic technology over the last two decades have enabled the development of cellular (mobile) phones to advance at a truly astonishing rate. A cellular (mobile) phone has its own central transmitter allowing it to receive seamless transmissions as it enters and exits a cell.
Some people believe the impact of the telephone has had on our lives is negative. Whatever your beliefs, it is un-doubtable that the invention and development of the telephone has had a massive impact on the way we live our lives and go about our every day business.
Article Source: http://EzineArticles.com/?expert=Jason_Morris
1. 1874 - Principal of the telephone was uncovered.
2. 1876 - Alexander Graham Bell invents the telephone, beating Elisha Gray by a matter of hours.
3. 1877 - The very first permanent outdoor telephone wire was completed. It stretched a distance of just three miles. This was closely followed in the U.S. by the worlds first commercial telephone service.
4. 1878 - The workable exchange was developed, which enabled calls to be switched between subscribers rather than having direct lines.
5. 1879 - Subscribers began to be designated by numbers and not their names.
6. 1880's - Long distance service expanded throughout this period using metallic circuits.
7. 1888 - Common battery system developed by Hammond V. Hayes, allows one central battery to power all telephones on an exchange, rather than relying on each units own battery.
8. 1891 - First automatic dialling system invented by a Kansas City undertaker. He believed that crooked operators were sending his potential customers elsewhere. It was his aim to get rid of the operators altogether.
9. 1900 - First coin operated telephone installed in Hartford, Connecticut.
10. 1904 - "French Phone" developed by the Bell Company. This had the transmitter and receiver in a simple handset.
11. 1911 - American Telephone and Telegraph (AT & T) acquire the Western Union Telegraph Company in a hostile takeover. They purchased stocks in the company covertly and the two eventually merged.
12. 1918 - It was estimated that approximately ten million Bell system telephones were in service throughout the U.S.
13. 1921 - The switching of large numbers of calls was made possible through the use of phantom circuits. This allowed three conversations to take place on two pairs of wires.
14. 1927 - First transatlantic service from New York to London became operational. The signal was transmitted by radio waves.
15. 1936 - Research into electronic telephone exchanges began and was eventually perfected in the 1960's with the electronic switching system (SES).
16. 1946 - Worlds first commercial mobile phone service put into operation. It could link moving vehicles to a telephone network via radio waves.
17. 1947 - Microwave radio technology used for the first time for long distance phone calls.
18. 1947 - The transistor was invented at Bell laboratories.
19. 1955 - Saw the beginning of the laying of transatlantic telephone cables.
20. 1962 - The worlds first international communications satellite, Telstar was launched.
21. 1980's - The development of fiber optic cables during this decade, offered the potential to carry much larger volumes of calls than satellite or microwaves.
22. 1980's, 1990's, to present - Huge advances in micro electronic technology over the last two decades have enabled the development of cellular (mobile) phones to advance at a truly astonishing rate. A cellular (mobile) phone has its own central transmitter allowing it to receive seamless transmissions as it enters and exits a cell.
Some people believe the impact of the telephone has had on our lives is negative. Whatever your beliefs, it is un-doubtable that the invention and development of the telephone has had a massive impact on the way we live our lives and go about our every day business.
Article Source: http://EzineArticles.com/?expert=Jason_Morris
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| Cell Phone User |
