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

Timeline of Telecommunications What is a telephone? How Telephone was invented? What telephones are used for? How does telephone works? How voices are being transmitted between telephones?

How does telephone works? Two-piece telephone set Cordless phone Cellular phone (Mobile phone)

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

Advances in Technology (II) In the 1950s the technology of the coaxial- cable system was combined with high- reliability vacuum-tube circuits The application of digital techniques to transmission Undersea cable and satellites

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

Multifunctional telephones Use microprocessors and integrated circuits Automatic answering and message- recording capability. Automatic answering and message- recording capability. Videophones are devices that use a miniature video camera to send images as well as voice communication

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

The new 3G Cell phone Technology Third generation (3G) services combine high speed mobile access with Internet Protocol (IP)-based services. Third generation (3G) services combine high speed mobile access with Internet Protocol (IP)-based services.

What will 3G mean to users? With access to any service anywhere, anytime, from one terminal, the old boundaries between communication, information, media and entertainment will disappear. Services will truly converge

TECHNOLOGYFEATURES AMPS Advanced Mobile Phone Service-Analog voice service - No data service 2GCDMACode 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 TDMATime Division Multiple Access GSMGlobal System for Mobile Communications PDCPersonal digital cellular 3GW-CDMAWide-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-2000Based on the Interim Standard-95 CDMA standard TD-SCDMATime-division synchronous code- division multiple-access 1G

3G is designed to deliver: Advanced, lightweight, easy-to-use terminals with intuitive interfaces Instant, real-time multimedia communications Global mobility and roaming A wide range of vendors and operators, offering choice, competition and affordability High-speed and Internet access

3G Cell Phone Videophone Simulation