History of telecommunications

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History of telecommunications
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History of telecommunications

• Messaged carried by men, ship, animals
• Earliest distance communications - smoke signals
  (North America and China) and drums (Africa, New
  Guinea and South America)
• Europe - 1790s - fixed semaphore systems -
  information is conveyed by means of visual
  signals, using towers with pivoting shutters,
  also known as blades (paddles)
• 1792 visual telegraphy (semaphore) between
  Lille and Paris

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History of telecommunications

• 1809 - 'electrochemical' telegraph - German
  physician, anatomist and inventor Samuel Thomas
  von Sömmering
• 1832 - electromagnetic telegraph - Baron
  Schilling, Russia - short-distance transmission
  of signals between two telegraphs in different
  rooms, tested on a 5 km experimental underground
  and underwater cable
• 1833 - Carl Friedrich Gauss and Wilhelm Weber,
  Germany - communicate over a distance of 1200 m
  within Göttingen achieve distant needle move in
  the direction set by the commutator on the other
  end of the line
• developed signals, own alphabet encoded in a
  binary code which was transmitted by positive or
  negative voltage pulses which were generated by
  means of moving an induction coil up and down
  over a permanent magnet and connecting the coil
  with the transmission wires by means of the
  commutator

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History of telecommunications

• 1836 David, American - the first known American
  electric telegraph
• 1836 - the telegraph - developed by Samuel Morse
  (until he was 34, he was a painter!) and Alfred
  Vail (USA) - transmitting over long distances
  using poor quality wire Vail - developed the
  Morse code signaling alphabet with Morse
• 1837 - the first commercial electrical telegraph
  - Sir William Fothergill Cooke and Charles
  Wheatstone, England patented as an alarm
  system successfully demonstrated Euston and
  Camden Town (London)

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History of telecommunications

• 1843 - U.S. Congress appropriated 30,000 to fund
  an experimental telegraph line from Washington,
  D.C. to Baltimore
• 24 May 1844 - first public demonstration by Morse
  of his telegraph - a message from the Supreme
  Court Chamber in Washington to the BO Railroad
  in Baltimore
• 1861 - the first transcontinental telegraph
  system (USA)
• 1866 - the first successful transatlantic
  telegraph cable between Ireland and
  Newfoundland
• reduced communication time to a matter of a few
  hours, allowing a message and a response in the
  same day !!!

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History of telecommunications

• 1861 - Johann Philipp Reis, Germany - first
  telephone couldnt interest people in Germany
  in his invention
• 1876 Alexander Bell Bell's patent 174,465, was
  issued to Bell on March 7
• Elisha Gray also experimenting with acoustic
  telegraphy and files a patent application 3 hours
  after Bell with the U.S. Patent Office for a
  telephone - Bell got the patent

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History of telecommunications

• 1878 Microphone Edison (General Electric)
• 1878 - First Telephone Exchange in New Haven, USA
  - 21 listings
• Mid-1880s - telephone exchanges in every major
  city of the United States
• 1832, James Lindsay (UK) - classroom
  demonstration of wireless telegraphy 1854, he
  demonstrated a transmission across the Firth of
  Tay from Dundee to Woodhaven (3 km), using water
  as the transmission medium

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History of telecommunications

• 1884 Radio Telegraph Popov
• 1892 First Automatic Telephone Exchange in La
  Porte USA by Strowger
• 1896 Radio Telegraph Marconi (Italy)
• 1898 First Automatic Telephone Exchange in
  Germany
• 1901 Marconi - wireless communication between
  Britain and Newfoundland, earned the Nobel Prize
  in physics in 1909

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History of telecommunications

• 1918 Radio Carrier System /USA 1920 Radio
  Broadcasting
• 1925 John Baird, Scottish - demonstrated the
  transmission of moving silhouette pictures in
  London
• 1929 - Bairds work formed the basis of
  semi-experimental broadcasts done by the British
  Broadcasting Corporation

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History of telecommunications

• 1927 demonstration of the cathode ray tube
  (CRT) in broadcasting of images CRT inventor
  was Karl Braun in 1897
• 1930 Coaxial cables
• 1931 Radiolinks
• 1937 Pulse Code Modulation - PCM (64kbps) Reeves
  (Bell Labs) - representation of a signal by a
  series of digital pulses firstly by sampling the
  signal, quantizing it and then encoding it a
  method developed in the seventies

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History of telecommunications

• 1945 - Arthur C. Clarke proposes the idea for
  Synchronous Orbit Satellites
• 1946 Cellular Radio (Bell Labs) remained
  costly and not widely used until 1995
• 1947 Transistor (Bell Labs)
• 1957 Sputnik, USSR first satellite
• 1962 Telstar - first active, direct relay
  commercial communications satellite

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History of telecommunications

• 1960 first LASER (Light Amplification by
  Stimulated Emission of Radiation) Theodore Maiman
  , USA
• 1960 - ATT installs first electronic switching
  system in Morris, IL
• 1961 - Electronic Telephone Exchange (Bell Labs)
  T-1 Carrier System (Bell Labs) TDM (Time Domain
  Multiplexing) - 24 channels 64 Kbps, 1.544 Mbps
  (mega bits per sec)

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History of telecommunications

• 1965 - ATT introduces stored program controlled
  switching
• 1966 - Fibre Glass optics - Kao Hockman,
  Standard Telecom Labs
• 1967 - Larry Roberts paper proposing ARPANET,
  Advanced Research Projects Agency
• 1969 - The Department of Defense initiates the
  ARPANet, which led to the development of Internet
  - initially computers at Stanford University and
  UCLA are connected

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History of telecommunications

• 1969 ISDN (Integrated Services Digital Network
  2x64k16k)
• 1970 Aloha-network (Hawaii)
• 1974 Packet and Circuit Switched data networks
  (CCITT X.25 and X.21) - International Telegraph
  and Telephone Consultative Committee (CCITT,
  from French Comité Consultatif International
  Téléphonique et Télégraphique)

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History of telecommunications

• 1974 Arpanet/ Internet DoD/USA
• 1974 - Vint Cerf and Bob Kahn discuss connecting
  networks together to form an "internet". They
  collaborate in creating a Transmission Control
  Protocol (TCP).
• 1976 Optical Fiber in data transmission
• 1977 Ethernet 10Mbps Xerox (developed in 1974),
  Ether is the mysterious invisible fluid that
  transfers heat, originally based on the ALOHA
  radio protocol

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History of telecommunications

• 1972 Mobile Networks ARP
• 1978 ISO/OSI CCITT x.200 (the standard
  describing the OSI model)
• 1984 MHS (Message Handling System) CCITT/ISO
• ODA (Open Document Architecture) CCITT/ISO
• 1984 Intelligent Networks (AIN Series)
  Bellcore
• 1987 GSM (Groupe Special Mobile, CEPT) -
  Global System for Mobile Communications

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History of telecommunications

• 1987 - Bellcore introduces the Asymmetric Digital
  Subscriber Line (ADSL) concept which has the
  potential of multimedia transmission over the
  nation's copper loops
• 1989 HTTP/HTML in Cern by Tim Barners-Lee -
  Hypertext Transfer Protocol (a protocol i.e. set
  of procedures describing how to pass information)
  /HyperText Markup Language (language how to
  present information that passes via HTTP)

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History of telecommunications

• 1991 - ATM (Asynchronous Transfer Mode 155 Mb/s)
• 1991 - IN CS.1 (Intelligent Networks) by ITU and
  ETSI
• 1992 - WWW (World Wide Web) - the first audio
  and video multicasts are broadcast over the
  Internet
• 1993 - Internet browser MOSAIC is introduced at
  the University of Illinois

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History of telecommunications

• 1998 GPRS (General Packet Radio System)
• 2001 UMTS (Universal Mobile Telecommunication
  System)

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Terminal Complex

• First computer telecommunication systems - early
  60s local multi-user systems - terminal
  complex
• Classical Terminal Complex - shares computer
  resources among closely located users via
  telecommunication lines
• Computer configuration (CPU / RAM / Channel
  (usually phone line))
• Transmission medium
• wires/cables pairs or cable set of pairs
  twisted pairs for reduction of signal
  interference coaxial cables (noise shield)

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Terminal complex
I/O system
I/O interface
CPU
I/O channel
RAM
Multiplexor
Telephone exchange

• ...

Modem
Modem
Modem
Terminal

• Link channels

Modem
Modem
Link channels

• Modem

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Terminal Complex

• Information transmission methods
• Synchronous byte-stream forming data blocks,
  synchronization based on
• additional signals in control lines
• synchro-symbols in the front and in the end of
  the block
• advantage higher speed, less communication
  overload
• drawback more complicated hardware, buffer
  memory
• application high speed communication
• Asynchronous 1 start impulse and 1 or 2 stop
  impulse clock frequency is higher than the
  read-write frequency (access instants)
• advantage no buffering, simple synchronization
  circuit
• drawback communication overload (30)
• application slow terminals in short distance

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Terminal Complex

• Information transmission modes
• Terminal complexes use mostly phone/telegraph
  lines on
• switched lines use the public exchange by dialed
  access from point to point
• advantage chipper
• drawback slower, noisy
• application smaller traffic
• leased lines fixed lines for monopoly use from
  point to point connection line is owned of local
  PTT company
• advantage reliable error-free, faster,
  promptness
• drawback price
• application bigger traffic

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Terminal Complex

• Standard Interface
• usually bus of 30-60 signal lines
• physical parameters line length signal
  parameters (amplitude, frequency, working mode
  monopoly, multiplex, block-multiplex)
  multiplexors number
• Multiplexor
• transforms parallel (byte) stream from terminals
  to sequential (bit) stream for the channel
  interface
• addressing the terminals - 2 methods cycle
  time-driven or event driven selection
• error control
• same functions in opposite direction (from
  channel to terminals)

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Terminal Complex

• Modems (signal MODulator/DEModulator) phone line
  transmission with digital to analog and analog to
  digital conversion
• Structure and components
• Modulator (data input)
• Demodulator (data output)
• Filter (frequency separator)
• Linear Amplifier
• Modulation types
• AM
• FM
• PhM

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Modulations