PHONES
great invention!!!
A telephone, or phone, is a  telecommunications device. The first telephones were directly connected to each other from one customer`s office or residence to another customer`s location. Being impractical beyond just a few customers, these systems were quickly replaced by manually operated centrally located switchboards. This gave rise to landline telephone service in which each telephone is connected by a pair of dedicated wires to a local central office switching system, which developed into fully automated systems starting in the early 1900s. Hand-held mobile phones were introduced for personal service starting in 1973. By the late 1970s several mobile telephone networks operated around the world. Today, the worldwide public switched telephone network, with its hierarchical system of many switching centers, can connect any telephone on the network with any other.
The history of phones
The concept of the telephone dates back to the string telephone or lover`s telephone that has been known for centuries, comprising two diaphragms connected by a taut string or wire. Sound waves are carried as mechanical vibrations along the string or wire from one diaphragm to the other. The classic example is the tin can telephone, a children`s toy made by connecting the two ends of a string to the bottoms of two metal cans, paper cups or similar items. The essential idea of this toy was that a diaphragm can collect voice sounds from the air, as in the ear, and a string or wire can transmit such collected voice sounds for reproduction at a distance.
Invention of the phones
Antonio Meucci, 1854, constructed telephone-like devices.
Johann Philipp Reis, 1860, constructed prototype `make-and-break` telephones, today called Reis telephone.
Alexander Graham Bell was awarded the first U.S. patent for the invention of the telephone in 1876.
Elisha Gray, 1876, designed a telephone using a water microphone in Highland Park, Illinois.
Tivadar Puskás proposed the telephone switchboard exchange in 1876.
Thomas Edison invented the carbon microphone which produced a strong telephone signal
INVENTORS
the phone
the phone
Stay connected anytime and anywhere
SMS
Your way out in emergencies
Navigation in your hand
Mini PC
Enhance your business
Enhance your business
Help in legal matters
Wholesome entertainment
Transfer of data
Prestige and fashion statement
benefit of the phone
effect of phone
Teen Tendonitis
Stress
Sleep Loss
Accidents
Increases Anxiety
Risk Of Cancer
Cyber Bullying
Thank you for your watching!!!!!!!!