is an apparatus that transmits mechanically along wire or string vibrations in a diaphragm
caused by voice or sound waves to a distant similar diaphragm that produces sounds. In
other words, it is an instrument that sends and receives voice messages by converting them
into electrical energy to be transported to great distances. Telephony refers to the art
and practice of electrical speech transmission, including the many systems, accessories,
and operating methods used for this purpose.
Alexander Graham Bell was a famous Scottish inventor born on March 3, 1847, in Edinburgh,
Scotland and died on August 2, 1922. He was known as the "inventor of the
telephone." Bell studied at the Universities of Edinburgh and London.
His mother, Eliza Grace Symonds, was a musician and a portrait painter. Hisfather,
Alexander Melville Bell, was a teacher and author on correct utterance. He was known as
the inventor of "visible speech", which was a code that demonstrated the
positioning and behavior of the tongue, throat, and lips while producing sounds. The irony
of this fact was that by the time A. Graham was twelve years old his mother lost her
hearing. Thus encouraging his interest in the production of sounds. By 1866, Bell
performed a series of experiments to determine how vowel sounds were produced. To
make vowel sounds he combined the notes of electrically driven tuning forks, which gave
him the idea of telegraphing speech.
The discovery of the
telephone actually originated from a casualty. Alexander G. Bell actually attempted to
create a telegraph that would send several messages through the same wire simultaneously.
However, the components of his experimental telegraph were not quit in the right place,
which prevented it from working well.
When he tested his failing instrument, he came up with a successful idea on how to
produce voices from a distance. Then he began working on sound transmission for the
deaf and discovered that steady electric current could be adjusted to resemble the
vibrations made by the human voice. Bell then created a transmitter and receiver. On March
7,1876, he patented a device, which he called the "telephone" that transmitted
human voices along wires. He tested this device with his assistant, Thomas A. Watson, to
later find out it was successful. Three days after he patented his mechanism the first
words were transmitted by Bell ."Watson--come here--I want you."
In this period of time, each persons telephone line had to be connected directly to
another persons telephone in order to communicate. Nonetheless, this product was
still not ready for public use. By 1877 switchboards were created. The first switchboard
was installed in Boston. It established direct connection to a phone operator. Telephones
were wired to the central switchboard. To make a phone-call people would pick-up the
telephone and tell the operator to connect his or her call to another certain person.
The fact that these
local operators could overhear a person's conversation motivated Almon B. Strowger, a
mortician, to create a device that would provide privacy. He patented a central office
switch in1891. In this same year, on March 10, he was given a patent for his invention,
the "eleven digit dial," which led to the eleven digit desk telephone (telephone
that contained eleven digits). Later, the Strowger Automatic Exchange was established.
In1896, the A. B. Strowger Company created the First Dial. In this same year Almon
Strowger retired. In 1901, the A. B. Strowger Company was renamed to Automatic Electric
Company. By the early part of the century, the Automatic Electric Company's dial exchanges
were rapidly expanding.
The Bell System suddenly became interested in the dial, as it was expanding, and purchased
a license to fabricate a dialing apparatus. Once Bell received its license, the Western
Electric Company, which became Bell's manufacturer in 1880, began the manufacturing in
January 1919 and on November 8, 1921 the "first Bell System large machine switching
exchange was put into service in Norfolk, VA." In 1905, the Automatic Exchange
Company operated entirely from a central battery (power for speech) in South Bend, IN.
Later, the Strowger's company
was renamed, once again, to GTE.
The Wilhelm Telephone Mfg. Company of Buffalo, New York, was formed in November 1898 by
Walter Wilhelm, an electrician who tried several times to sell his transmitter to the Bell
System. The transmitter contained two separate diaphragms and chambers. The Bell
System tested the transmitter but decided that it would not suit their objective. By
1913, the company ceased operations.
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In 1894, when the
Bell patents expired, the "field of telephony was opened to the public." During
the dates of the patents, the Bell Telephone Company created a monopoly. Many manufactures
of telephones began to emerge. An example of one of these companies is the Columbia
Telephone Manufacturing Company of New York City.
Not very much is known about this company, although, the telephones were manufactured
under the patents of James McDonough and H.H. Eldred.
The entire Columbia Telephone Company was assembled and manufactured by the company in its
New York factory. Telephone advertisements began to appear during the year of 1894 for the
In1986, there were approximately 600 million telephones in19,000 local offices, 933 toll
offices, 168 primary offices, 52 sectional office and 10 regional offices.
In 1998, Seven Guys Telecom (7GT) was formed. Headquarters were established in Ranlo, NC.
What was Strowger's Central
The central office switch is the vanguard to PBX (Private Branch Exchange) telephone
systems. A central office switch is located centrally and directs calls in the public
network between users. This allows the calls to be private and eliminates the necessity of
having each individual's telephone line wired directly to other individual users. A PBX
also eliminates the need to have each person's telephone line connected to the central
office. People 's calls could be transferred directly, with no interference, simply by
having their telephone lines connected to a PBX. To connect a phone line to a PBX the
local telephone company would bring telephone lines to an interface to which external
lines were wired. This interface was called a "jack." There are two kinds of
jack that holds a single line (rj11c), found in most homes.
2. A jack that can hold multiple lines (rj21x), found in