Invention of TelephoneInvention of Telephone

                                                                       

                                                                       

                                                                       

                                                                                                                                                                                                                                                                                               

Alexander Graham Bell

Best known for inventing the telephone, Alexander Graham Bell was a passionate educator and innovator throughout his life. He developed the telephone, then went on to experiment with ideas ranging from the recording cylinder (precursor of phonograph records) to hydrofoil boats.

Alexander Graham Bell constructed this prototype telephone in Alexander Graham Bell constructed this prototype telephone in 1875. The device consists of a coil of wire, a magnetic arm and a 1875. The device consists of a coil of wire, a magnetic arm and a taut membrane. Any sound causes the membrane, and hence the taut membrane. Any sound causes the membrane, and hence the magnetic arm, to vibrate. The movement of the magnet induces a magnetic arm, to vibrate. The movement of the magnet induces a fluctuating electric current in the coil. This electrical signal can be fluctuating electric current in the coil. This electrical signal can be reconverted into sound by an identical apparatus at the other end reconverted into sound by an identical apparatus at the other end of the circuit.of the circuit.

•Alexander Graham Bell's Telephone

Timeline of Telecommunications Timeline of Telecommunications

What is a telephone?What is a telephone?

How Telephone was invented? How Telephone was invented?

What telephones are used for? What telephones are used for?

How does telephone works?How does telephone works?

How voices are being transmitted betweeHow voices are being transmitted between telephones? n telephones?

How does telephone works?How does telephone works?

Two-piece telephone setTwo-piece telephone set

Cordless phoneCordless phone

Cellular phone (Mobile phone)Cellular phone (Mobile phone)

Advances in Technology (I)Advances in Technology (I)

The invention at the end of the 19th centurThe invention at the end of the 19th century of the loading coil (a coil of copper wire y of the loading coil (a coil of copper wire wound on an iron core and connected to thwound on an iron core and connected to the cable every mile or so) e cable every mile or so) Repeaters, electromechanical devices spaRepeaters, electromechanical devices spaced along the route of the call which amplifced along the route of the call which amplified ied The invention of the triode vacuum tube, The invention of the triode vacuum tube, which amplified electrical signals. which amplified electrical signals.

Advances in Technology (II)Advances in Technology (II)

In the 1950s the technology of the coaxial-In the 1950s the technology of the coaxial-cable system was combined with high-cable system was combined with high-reliability vacuum-tube circuits reliability vacuum-tube circuits

The application of digital techniques to The application of digital techniques to transmission transmission

Undersea cable and satellites Undersea cable and satellites

Recent Developments Recent Developments

Radio into the telephone set and cell Radio into the telephone set and cell phonephone

In addition to regular telephone service, In addition to regular telephone service, modern cellular phones also provide modern cellular phones also provide wireless Internet connections, enabling wireless Internet connections, enabling users to send and receive electronic mail users to send and receive electronic mail and search the World Wide Web. and search the World Wide Web.

Multifunctional telephones Multifunctional telephones

Use microprocessors and integrated circuitUse microprocessors and integrated circuits s

Automatic answering and message-recorAutomatic answering and message-recording capability.ding capability.

Videophones are devices that use a miniatVideophones are devices that use a miniature video camera to send images as well aure video camera to send images as well as voice communication s voice communication

Future Development Future Development

Digital technology, such as Digital SubscriDigital technology, such as Digital Subscriber Line (DSL) or Integrated Services Digitber Line (DSL) or Integrated Services Digital Network (ISDN), to allow users to get mal Network (ISDN), to allow users to get more information faster over the telephone. ore information faster over the telephone. Fiber optic cable to meet the ever-increasiFiber optic cable to meet the ever-increasing demand for increased bandwidth. ng demand for increased bandwidth. New 3G Cell phone Technology New 3G Cell phone Technology

The new 3G Cell phone TechnologThe new 3G Cell phone Technology y

Third generation (3G) services combine Third generation (3G) services combine high speed mobile access with Internet high speed mobile access with Internet Protocol (IP)-based services. Protocol (IP)-based services.

What will 3G mean to users?What will 3G mean to users?

With access to any service anWith access to any service anywhere, anytime, from one terywhere, anytime, from one terminal, the old boundaries betminal, the old boundaries between communication, informaween communication, information, media and entertainment tion, media and entertainment will disappear. Services will trwill disappear. Services will truly converge uly converge

TECHNOLOGY FEATURES

AMPS Advanced Mobile Phone Service -Analog voice service- No data service

2G CDMA Code Division Multiple Access

- Digital voice service- 9.6K to 14.4K bit/sec.- CDMA, TDMA and PDC offer one-way data transmissions only- Enhanced calling features like caller ID- No always-on data connection

  TDMA Time Division Multiple Access

  GSM Global System for Mobile Communications

  PDC Personal digital cellular

3G W-CDMA Wide-band Code Division Multiple Access

- Superior voice quality- Up to 2M bit/sec. always-on data- Broadband data services like video and multimedia- Enhanced roaming

  CDMA-2000 Based on the Interim Standard-95 CDMA standard

  TD-SCDMA Time-division synchronous code-division multiple-access

1G

3G is designed to deliver: 3G is designed to deliver:

Advanced, lightweight, easy-to-use terminAdvanced, lightweight, easy-to-use terminals with intuitive interfaces Instant, real-timals with intuitive interfaces Instant, real-time multimedia communications e multimedia communications

Global mobility and roaming A wide range Global mobility and roaming A wide range of vendors and operators, offering choice, of vendors and operators, offering choice, competition and affordability High-speed competition and affordability High-speed e-mail and Internet access e-mail and Internet access

3G Cell Phone

Videophone Simulation

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