A Historical Overview of Telecommunications

1. A Historical Overview of Telecommunications Dr. Farid Farahmand CET 533

2. A Moment to Reflect…. “I don’t really foresee any commercial possibilities for COMPUTERS and I predict a world market for maybe FIVE computers!” Thomas Watson, 1940, Chairman of IBM Mark I; brainchild of Howard H. Aiken; 1939-1944

3. Today….. • Over one billion people are using computers to access Internet services • Over 244 billion messages are sent every month • In 2006, the total number of cell phones in the world was estimated to be one-billion “Worldwide Internet traffic is (almost) doubling every year.”

4. Consider…… • Non-scientists inventions! • Examples • Morse – Art teacher • Bell – Teaching deaf students wanting to become rich • Strowger – undertaker • Josephine Cochrane – rich party lady! • Characteristics • Visionary • Ignoring the complexity • Strong will • Lucky • Lack of support! • “Telegraph system not practical!” • “Telephone system is useless!” • Continues battle to gain power and control! • Establishing monopoly! • Bell refusal to connect! • ATT refusal to use others’ phones • People seeking profit

5. Invention of Telegraph/Telephone (1845-1920) • Birth of telecommunications: telegraph and telephones • 1845 to 1876 • 1876 to 1920 • 1920 to 1950 • 1950 to 1970 • 1970 to 1990 • 1990 to 2000

6. Telecom Evolution… Regulatory Changes Data Communications - Various media Technological Breakthrough Telephone - Sending voice Telegraph - Magnetism

7. 1845 to 1876 • Discovery of magnetism by Hans Oersted • Current causes the campus needle to move! • Andre-Marie Ampere explained the force between electric currents: two parallel currents in the same direction attract, in oposite directions repel. • Michael Faraday built the first electromagnetic

8. 1845 to 1876 • Samuel Morse invented the telegraph relay • Send telegraph messages along wires • Invented Morse code • Proposed the invention to the Postal service: “Interesting but no thanks” • Others were very interested • Railroad, Newspapers • By 1870 Western Union was offering telegraph services in almost every region • After the war WU turned into a financial giant • Telegraph services seem very profitable • By this time sending messages over wire was nothing magical

9. 1876 to 1920 • Many new inventions • Light bulb, Refrigerator, Camera, Telegraph • Many thought the only way to get rich was by inventing something! • Alexander Graham Bell was no exception • He started working on sending sound over wire • Transforming sound to electrical waves and then back to sound • Following his “voice box” invention, he started seeking financial backup • In 1877 Bell Telephone Company was formed • Investors were not convinced that the new “Voice Box” will be very popular and profitable • They wanted to sell the patent to Western Union: Once again: “Interesting, but no thanks; already have telegraph!”

10. 1876 to 1920 • 1878 - First commercial switchboard in New Haven, CT. 21 telephones on 8 lines • Bell Telephone started to offer telephone services • Started with New England • In just a few years the demand was overwhelming • Western Union, feeling miserable, wanted a piece of the profit • Use Elisha Gray’s telephone patent • They had the telegraph infrastructure • Bell files a law suit against WU -> WU backed off from offering the idea

11. 1876 to 1920 • So, Bell telephone started monopolizing the telephone services • Bell was only obligated to pay WU a monthly fee • Bell started selling franchise licenses • Known as Bell Operating Companies (BOCs) later known as Regional BOCs (RBOCs) • The situation went on until 1893 will minimal government regulations • In 1893 the telephone patent expired! • Independent companies were all ready to use the opportunity • Within a few years Bell Telephone only had 50% of subscribers • One of the big competitors was GTE

12. 1876 to 1920 • Bell was refusing interconnection to Independent companies • Independent companies started filing law suits • About the same time Bell was struggling with a major financial problem • AT&T became the mother company having all controlling power • Lucky for AT&T J.P.Morgan sees a major opportunity and rushes to help! • Morgan starts buying all independent companies, including the WU • Once again communication monopoly is established, starting 1900

13. 1876 to 1920 • The monopoly continued until 1913 when AT&T agreed to compromise • Allowing interconnections • Diversifying its stocks • Stop buying other independent companies • In return, AT&T will be guaranteed to keep all its services!

14. Evolution of Network • Consisting of many different developments in different areas • Central Office • Transmission Network • Data Communication Network • Long Distance Network

15. Central Office Developments • Initially all connections were through dedicated lines [FIGURE] • 1000 users (2).1000dedicated lines • N(N-1) lines for N users to be fully connected! • Major developments [FIGURE] • Main Distribution Frame (MDF) connected to Switching Boards in the Central Office • Using Shared Ports and Trunks • Connections will be through patch panels • Users were at the mercy of the operators!

16. Wired world!

17. 50 x 50 Switchboard

18. Electromechanical Switches • Believing that the operator is working in favor of his competitor undertaker, Armond Strowger wanted a system which eliminates the need for operators • Strowger invented the step-by-step switch in 1898 • Built the a mechanical switch and introduced the first rotary dial telephone set • He called it the "girl-less, cuss-less" telephone system • SxS Switch! • Worked well all the way through 1970 • The system replaced the old switchboard

19. Step-by-Step Mechanical Switch

20. Signaling • Why signaling? • Notifying when a call arrives (ringing) • Identifying who the call goes to (Dial Tone) • Specifying the status of the receiver (Busy Tone) • Identifying when the call is over (Termination) • Historically all these could be done by Yelling: “A call for Armando” • Thomas Watson invented the Ring • Upon receiving a call a bell started ringing using AC current • Routing was based on family name!

21. Customer Equipments • Telephone monopoly • All phones belonged to the Bell Telephone company – customers were renting it • Bell phones were made by different companies and were not very reliable • Western Electric (founded by Elisha Gray) made the best phones • So Bell bought them out! (Kind of like Microsoft!) • Bell Telephone Company had complete control over standardizing the phone technology- until 1960_

22. Customer Equipments • Main changes in phone sets • Combining TX and RX in the handset • 1920 Bakelite telephones replaced the wood phones – single handset with a small rotary dialer • Bakelite [bey-kuh-lahyt, beyk-lahyt]is synthetic thermosetting resin (plastic like material) used for insulating electrical apparatus (since it is a nonconductor)

23. Long Distance • First long distance call established between Boston and Providence (1881) • Long Line Networks (FIGURE)

24. Telephone Poles

25. Evolution of Telecommunications21st Century: 1920-to 2000 • Based on regulatory laws and technological breakthroughs • 1920 to 1950 • 1950 to 1970 • 1970 to 1990 • 1990 to 2000

26. 1920 to 1950 • Regulating the cost of telephone service by FCC (Federal Communication Commission) • Reliable systems (99.999%) • Universal Service Concept • Long distance calls can subsidize cost of local calls • Business lines are still more expensive in some areas! • By 1950 every rural area in US had access to long distance

27. 1920 to 1950 • Crossbar Switches were invented • No more manual switching • Larger capacity • Allowing direct long distance calls using 1 prefix • Frequency Division Multiplexing • Aggregating multiple calls on a single line – less copper!

28. Requires n2 Switches!

29. 1950 to 1970 • Foreign attachments could be connected to phone lines • PBX (Privet Branch Exchange) boxes were allowed on customer premises • More independent companies got into phone business • First analog stored program controlled switches were invented in 1970 • Smaller, higher capacity, more reliable, less space, less power • Result: More competition!

30. 1950 to 1970 • Microwave technology started being used for long distance • The technology was initially used by military during WW II • MCI was the leading company to use this new technology • Air was being used as the transport medium • Polyethylene and Polyurethane-insulated cables • Less noise, better insulation, more cables pairs packed together • Touchtone phones • Use frequency to define each number (no more electromagnetic magnets)

31. Polyethylene Cables

32. 1970 to 1990 • Telephone monopoly by AT&T started eroding • Cheaper technology, less space requirements, less copper, lower maintenance cost, digital technology • More players and more competitions! • MCI wanted to get into long distance business using the microwave technology • In 1982 AT&T was broken down into seven RBOCs (Regional Bell Operating Companies) • AT&T kept its Western Electric, computer divisions, Bell Labs, and long distance services

33. 1970 to 1990 • Time Division Multiplexing • Conversion of voice into digital signals (Pulse Code Modulations – PCM) • Digital TDM was superior to FDM • No need for tuning amplifiers (used repeaters) • Les noise • In 1977 lightwave systems were introduced; first optical fiber introduced in 1968 • High capacity, low noise, more reliability • Requires more regeneration but much higher capacity • Used for long distance services • New technologies • Data communications • Cellular telephones • Real-time communication between mainframe and remote computers

34. 1990 to 2000 • Regulatory changes • The government started auctioning additional frequenting • Greater cellular network; more providers • 1996 Telecommunication Act: Deregulating local carriers • Allowing more competition in local phone services • The battle of CLECs and ILECs (Local Exchange Carriers) • Technological breakthroughs • Digital switches • Fast packet switching • Data communications • LAN, resource sharing, email

35. 1990 to 2000 • Technological breakthroughs • Transmission systems • SONET fiber optics (Synchronous Optical Network) • Interoperability between different venders • ISDN technology (Integrated Services Digital Network) • A new way to provide telephone service • All digital network – all the way to your house! • Providing two channels: voice and data • Expensive though, was not received well by the industry • Good technology at a bad time! • DSL (Digital Subscriber Line) • Providing high-speed data transmission: 6 million bits per second – compare with you 56K modem) • Uses the same copper pair as regular phone FIGURE

36. What we will be looking at…. Multiplexer Central Office Switch (Toll Office) Terminal Box TDM/FDM Digital/Analog Loop Carrier (last mile) Breakthroughs: Transmission system Switching systems Last mile Customer Equipments

37. Some Historical Points • the noun telephone is one of a class of technological and scientific words made up of combining forms derived from classical languages, in this case tele– and –phone. Tele– is from the Greek combining form tēle– or tēl–, a form of tēle, meaning “afar, far off,” while –phone is from Greek phōnē, “sound, voice.” Such words derived from classical languages can be put together in French or German, for example, as well as in English. • Alexander Graham Bell appropriated the word for his invention in 1876, and in 1877 we have the first instance of the verb telephone meaning “to speak to by telephone.” • The idea of the electric telegraph was born when the first experimenters with electricity noticed that electric charges could travel through wires over distances. In 1753 in Scotland Charles Morrison described a system of 26 wires for transmitting the 26 letters of the alphabet. Electrostatic charges traveling through these wires deflected suspended pith balls at the receiving station. However, this was never developed as a practical system. • Telex is a telegraphy system that transmits and receives messages in printed form.

38. References • http://www.telephonehistory.info/FL/Overview.html • http://home.speedfactory.net/cardwell/part1.html • http://cfp.mit.edu/resources/slides/jan05/Jamie_Telephony.pdf#search='first%20central%20office%2C%20New%20Haven‘ Good reference with interesting timeline • http://www.thg.org.uk/pwalker/xbar/sld001.htm on crossbar switches • http://www.privateline.com/Clipart/telecomclipart.html lots of good images • http://www.telephonesuk.co.uk/phones_pre1960.htm phone images