History of telecommunications

1. History of telecommunications IICT-BAS

2. 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

3. 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

4. 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)

5. 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 B&O 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 !!!

6. History of telecommunications 1861 - Johann Philipp Reis, Germany - first telephone – couldn’t 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

7. 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

8. 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

9. 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 - Baird’s work formed the basis of semi-experimental broadcasts done by the British Broadcasting Corporation

10. 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

11. 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

12. History of telecommunications • 1960 – first LASER (Light Amplification by Stimulated Emission of Radiation) Theodore Maiman, USA • 1960 - AT&T 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)

13. History of telecommunications • 1965 - AT&T 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

14. History of telecommunications • 1969 ISDN (Integrated Services Digital Network 2x64k+16k) • 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)

15. 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

16. 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

17. 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)

18. 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

19. History of telecommunications • 1998 GPRS (General Packet Radio System) • 2001 UMTS (Universal Mobile Telecommunication System)

20. 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)

21. Terminal complex T T T T T T Modem Modem Modem 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

22. 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

23. 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

24. 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)

25. 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

26. Modulations