Tài liệu lecture 1: Introduction to Telecommunications ppt

CSN200 Introduction to Telecommunications, Winter 2000 Lecture_01
Introduction to Telecommunications
CSN200
This course introduces students to modern data communications, including standards, techniques,
applications and devices involved in interconnecting computers in both local and wide area networks.

Reference:
Business Data Communications and Networking, 6
th
Edition, by- Fitzgerald and Dennis.


Data Communications:
Data Communications is the movement of computer information (digitized information) from one
point to another by means of electrical, electromagnetic or optical transmission systems.
Data communications usually includes only data.

Telecommunications:
Telecommunications is a broader term which includes the transmission of voice, graphics, images
and video as well as data.
Dictionary Meaning of the Word Telecommunication:
Tele means distance
Telecommunication means distant communication

Telecommunications refers to long-distance communication (the Greek tele means "far off"). At
present, such communication is carried out with the aid of electronic equipment such as the Radio,
Telegraph, Telephone, and Television. In earlier times, however, smoke signals, drums, light
beacons, and various forms of semaphore were used for the same purpose. The information that is
transmitted can be in the form of voice, symbols, pictures, or data, or a combination of these. The
physical equipment for a telecommunications system includes a transmitter, one or more receivers,
and a channel or means of communication such as the air, water, wire, cable, communications

satellite, or some combination of these.



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CSN200 Introduction to Telecommunications, Winter 2000 Lecture_01
Why Study Data Communications and Communications Network?
To fulfill the occupational need of the society:
•
In 1800s most countries were agricultural societies - needed farmers

•
In 1900s many countries had become industrial societies - labours

• As we approached 2000s we have moved into an information society, where the strategic
resource is information that must flow on communication network - dominated by
computers, data communications, networking and related highly skilled individuals
To reduce the Information lag:
•
Information lag is the time it takes for information to be disseminated around the world.



We will discuss:
•
History of Data Communications in North America

•
The Changing Nature of Information Systems

History of Telecommunications:


Compiled from:
Communications page by a group of German students:
/>History timeline by America's Public Broadcast Services:
/>
The history of communication begun in 3500BC using Abstract Signs, where paper was made from palm
trees and ink was made from oil and soot.

And the History of Telecommunication begun in 490 BC using messenger (40 kilometers long run).

One of the most famous events of "telecommunications" was the Marathon Run. In September 490
BC a terrible battle was going on at the coast of the Aegean Sea, near the town of Marathon. A small
well armed Greek army fought against a numerically stronger army of Persians, but nevertheless the
Greeks gained victory. The leader of the Greek army sent a courier with the message of victory back
to Athens. After the messenger had completed the more than 40 kilometers long run and reached the
streets of Athens, he collapsed with the words: "Be glad! We are the winners!" ... and died.

At that time fire signals were also used for communication.

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CSN200 Introduction to Telecommunications, Winter 2000 Lecture_01
360 BC : Water telegraphs store detailed information transmitted by smoke signals
150 BC : Net of smoke telegraphs over 3000 miles all across the Roman Empire
1794 : C. Chappe (France) develops an optical telegraph with its own alphabet
1809 : Electric telegraph by Samuel T. von Sömmering, Germany (35 wires)

1840 : Samuel F. B. Morse (USA) develops Morse code and improves telegraph
1844 : Electrical switch (relay) automatically writes transmitted information

Samuel F.B. Morse demonstrates his telegraph by sending a message to Baltimore
from the chambers of the Supreme Court in Washington, DC. The message, "What
hath God wrought?" marks the beginning of a new era in communication.




1850 : Telegraphy expands over national borders: sea cable England-France
1853 : Telegraph wires used in both directions simultaneously (duplex mode)
1861 : Philipp Reis, a German teacher, invents the telephone
1876 : Alexander Graham Bell (USA) take out patents for telephones


Scottish-American psychologist born 03. 03. 1847, Edinburgh died 02. 08. 1922,
Baddeck (Nova Scotia, Canada). First he was deaf and dumb teacher, later he dealt
with transformation of sound in electrical variations and vice-versa, developed the
first usable telephone (1876).
Alexander Graham Bell patents his telephone, built with the assistance of young
self-trained engineer Thomas A. Watson. Elisha Gray, who developed a similar
device at about the same time, unsuccessfully challenged Bell's patent.

1886 : Punched cards store census data in the USA for processing
1892 : Telephone uses dial, first automatic telephone exchange (no operator)
1894 : Wireless transmission of signals over two miles by the Italian physicist and engineer Marconi

Marconi began in 1894 with experiments on wireless transmission of radiowaves. In
1899 he sent information for the first time across the English Channel, in 1901 he

bridge over the Atlantic with his wireless telegraphy. In 1909 he became Nobel Prize
winner (with Braun).


1899 : Head of US Patent Office says: "Everything possible has been invented."
1902 : World wide radio communication on ocean ships (Morse code)
1906 : Electronics era begins: rectifier, triode, thermionic valve amplifier, etc.
1917 : AM transmitter: Modulation of a carrier frequency using speech signal
1919 : Binary memory (toggle switch) built of two triodes
1922 : Broadcasting stations commercialized (Russia, France, England, USA)

1928 : Mechanical Television
Baird Mechanical Television was broadcasting.

1927 : Electronic Television
Philo Farnsworth demonstrates the first electronic television for potential investors by
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CSN200 Introduction to Telecommunications, Winter 2000 Lecture_01
broadcasting the image of a dollar sign. Farnsworth receives backing and applies for a patent,
but ongoing patent battles with RCA will prevent Farnsworth from earning his share of the
million-dollar industry his invention will create.
1935 : Electronic Television
Philo Farnsworth and Vladimir Zworykin separately made great advances toward
commercial television and affordable sets.

1928 : Frequency modulation (FM) - higher sound quality for broadcasting
1931 : First electronic transmission of television images in Berlin
1935 : Multi-wire coaxial cables for communication purposes

1939 : Digital computer

John Atanasoff and Clifford Berry of Iowa State College complete the prototype of the first
digital computer. It can store data and perform addition and subtractions using binary code.
The next generation of the machine will be abandoned before it is completed due to the onset
of World War II.

1949 : Printed circuit boards for cheaper and easier placement of components
1951 : Howard H. Aiken develops large electromagnetic computer
1954 : Transistor radio, stereo recording, 76 meter radio telescope in England

1964 Operating System
IBM rolls out the OS/360, the first mass-produced computer operating system. Using the
OS/360, all of the computers in the IBM 360 family could run any software program.
Already IBM is a giant in the computer industry, controlling 70% of the market worldwide.
1965 Minicomputer
Digital Equipment introduces the PDP-8, the world's first computer to use integrated circuit
technology. Because of its relatively small size and its low $18,000 price tag, Digital sells
several hundred units.

1970 Optical Fiber
Corning Glass announces it has created a glass fiber so clear that it can
communicate pulses of light. GTE and AT&T soon begin experiments to
transmit sound and image data using fiber optics, which will transform the
communications industry.

1976 Super Computer
Cray Research, Inc. introduces its first supercomputer, the Cray-1, which can perform
operations at a rate of 240,000,000 calculations per second. Supercomputers designed by
Seymour Cray will continue to dominate the market; the Cray 2, marketed in 1985, will be
capable of 1,200,000,000 calculations per second.

1979 : Japanese Matsushita Inc. takes out a patent for Liquid Crystal TV screen
1980 : Videotext, Cable Television, Video Conferencing, Compact Disc
1983 : Personal Computers, Floppy Disks as storing device
PC's have taken the world by storm, dramatically changing the way people communicate;
IBM dominates the personal computer market, benefiting both from the production of its
own machines as well as "clones" produced by other companies.

1985 : Satellite navigation (both military and civilian applications)
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1990 : Hubble Telescope
The space shuttle Discovery deploys the Hubble Space telescope 350 miles above the Earth.
Although initial flaws limit its capabilities, the Hubble will be responsible for numerous
discoveries and advances in the understanding of space.


History of Communications in North America:
•
1837 Samuel Morse - Telegraph

•
1843, Alexander Bain - Printing Telegraph

•
1876, Alexander Graham Bell - Telephone

• 1874, Alexander (Sandy) Graham Bell developed the concept of the telephone at his
father's home in Brantford, Ontario.
• 1876, developed the first telephone capable of transmitting understandable conversion.

First long distance call was made from Paris, Ontario to Brantford, Ontario.
•
1879, Manual switchboards; automatic switching

•
Digital switching and digital circuits emerged in the 80's and 90's.

•
1948, First commercial Microwave link for telephone was in Canada

•
1962, First international satellite telephone over Telstar

•
1962, Fax was introduced

•
1963, Touch tone telephones

•
1969, Picture phone service

•
1969, Internet began as a network of US military and academic computers

•
1976, packet-switched network for computer data

•
1984, Breakup of AT&T (1885 - 1984), Increasing competition

•
1983, newer cellular telephone networks

•
1996, Deregulation Act, Open competition


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