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Chapter 9

Chapter 9. The Communications Infrastructure. Origins of Communications Infrastructure. What is the Communications Infrastructure? The underlying physical structure of communication networks Ancient Greeks, Romans and Chinese used fire to communicate over long distances

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Chapter 9

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  1. Chapter 9 The Communications Infrastructure

  2. Origins of Communications Infrastructure • What is the Communications Infrastructure? • The underlying physical structure of communication networks • Ancient Greeks, Romans and Chinese used fire to communicate over long distances • Limitations? Consume natural resources, susceptible to rain/fog/bad weather • Strengths? Can (in favorable weather) be seen for long distances, relatively inexpensive • The invention of the telegraph by Samuel Morse (1844) began the development of our modern infrastructure

  3. The Telegraph • Invented by Samuel Morse in 1844 • How did it work? Morse code. • Morse code is like digital communication except that instead of on/off, it was dot/dash (in electrical pulses) • http://www.scphillips.com/morse/trans.html • The first words sent? “What hath God wrought?” • By 1859 telegraph lines spanned the US • Dubbed: “Lightning lines” for their speed • In 1866 they connected the US and Europe via undersea cables • The telegraph began the general shrinking toward McLuhan’s global village • By enabling businesses, families, governments and militaries to communication with each other

  4. The Telephone • Alexander Graham Bell developed the earliest telephone in 1876 • Drastically reducing the value of the telegraph, and ushering in a new era of long distance communication • Having spilled acid on his lap, the first words transmitted to his assistant, “Mr. Watson, come here, I need you!” • Initially, the telephone was conceived of as a tool for mass media broadcasting • Popular world-wide at the turn of the 20th century • Declined in usage as a broadcast medium when radio emerged in the 1920s

  5. Telephony and Universal Service • Bell Telephone Company formed in 1877 • Began a series of vertical integration moves that enabled it to own most of the related businesses in the industry • Company is renamed as AT&T (American Telephone and Telegraph) • Continuing monopolistic actions, AT&T fears Antitrust lawsuit • Sherman Antitrust Act (1890) prohibits the restraint of free trade • They commit themselves to the principle of Universal Service in the Kingsbury Commitment • That everyone should have access to infrastructure networks (ie. A phone line) • Government lets “Ma Bell” reign as a natural monopoly—one that makes economic sense • AT&T expands to establish the first radio network, ultimately withdrawing to ownership of the infrastructure, not the stations

  6. The breakup of Ma Bell • The great depression lost AT&T substantial income, leading to major job loss and ultimately Government injunction • The FCC was formed in 1934 and began looking into AT&T’s business practices • Seeking to find out if they are anti-competition • The resolution? In 1984!! The Modified Final Judgement (MFJ) forced AT&T to sell off or divest its local phone companies into Regional Bell Operating Companies (PBOCs) • “The Baby Bells” ex., SBC (Southwestern Bell)

  7. Going Wireless • Wireless communication originated with Guglielmo Marconi’s Wireless telegraph (1896) • After WWII, wireless mircrowave systems replaced telephone lines for major city to city communication • Microwave transmission works through highly focused beams of radio waves • Satellites? Arthur C. Clarke (science fiction author) proposed microwave transmitters in space covering the globe with signals in 1945 • Became a reality in 1962 with AT&T’s Telstar

  8. Beginning of Broadband • AT&T (who else) built the first broadband infrastructure for network television • Using Coaxial cable and microwave transmission beginning in 1946 • Cable TV was born in 1948 (in places like Storrs) • The FCC blocked cable from entering into large city markets in 1966 to protect broadcast network television • Reversed the Ban in 1972 • In the 1970s satellites started serving as the primary option, including cable channels such as HBO (1975) • In 1995 Direct Broadcast Satellites (DBS) began to transmit TV into homes with mini-dishes • Fiber optics were introduced in 1977 and slowly replaced predecessors • 1990s saw coaxial cable being replaced, making way for digital cable and high speed internet

  9. Governmental Deregulation • Landmark legislation: Telecommunications Act of 1996 • Removed many restrictions on companies, primarily allowed telephone companies to carry cable signals and cable companies to provide telephone service • Was meant to reduce consumer prices and promote innovation through competition • Not yet entirely fulfilled • Resulted in massive cross-industry mergers • See AOL Time Warner (now Time Warner)

  10. Technology underlying the Infrastructure • Applied Electromagnetism and the Telegraph • Electricity causes iron to exhibit magnetic properties • Electric pulses triggered by a switch would cause a thin strip of metal to click up and down miles away (magnetized, demagnetized) • Short pulses were dots; Longer pulses were dashes • Still, telephone required shouting • AT&T (with Bell) developed the first repeater amplifier that would enable the speaker to speak at a normal level • First Transcontinental call NYC to San Francisco (1915) – Bell to Watson

  11. Infrastructure: Choice of Medium • 1880s saw massive number of telephone lines (and electrical ones) installed on poles • Too many lines—not practical (picture from 1890) • Too much interference from electrical wires • Problems led to further innovations and transmission media • Multiplexing (1918) – a way of transmitting multiple conversations over the same wires at the same time • Uses higher frequency “carrier waves” • Coaxial Cable (After WWII) – shields signal from interference typically found in single (or even twisted pair) phone wiring • Has the bandwidth to carry video and was shortly used to send television signals from one station to another • Eventually used to connect cable TV to homes

  12. Infrastructure: Choice of Medium (cont’d) • Microwave (1948) – though used in radar towers during WWII, it reached consumers in 1948 • At the time, 1000s of calls were multiplexed and sent through the air • Signals were amplified and relayed every 20-30 miles • Enabled First Coast-to-Coast Television connection in 1951 • Cable TV companies used it to get programming where antennas wouldn’t reach • Now used by TV mobile units to send signals back to the studio • Satellite (1945; 1962) – envisioned in the 40s, but AT&T makes it a reality in 1962. • Uses microwave signals to communicate • Sender has an uplink, the satellite has a transponder (receiver) and then the receiver on the ground has a downlink

  13. Infrastructure: Choice of Medium (cont’d) • Digital Carriers (1962) – the first digital telephone call was made using a T1 line (a digital carrier system) • T1 can carry 1.5 million bits of data per second, or 24 simultaneous conversations • Not fast enough? Try a T3 (at 45 million bits per second—that’s 45 Megabits!) • Fiber Optics (1977) – first systems were meant to replace the T1. • Based on the early designs of Bell’s photophone (1880) • Optical signals travel 100s of miles before fading (very little need for amplification) • This is the uber-fast transfer bringing VR to your neighborhood at over 1 Billion bits per second, a Gigabit per second!! • By the way… the speed keeps getting better—people keep finding ways to transmit light pulses more efficiently. Doubling the speed every 18 months!

  14. Data Switching Technology • Switching directs information to its intended destination—these devices have also evolved • Manual Switching (1920’s heyday) – Manual operators using an actual switchboard as seen in the movies • Automatic Switching (1951) – this was the first time that long distance calls could be made directly from the home (without operators) thanks to automatic switching • 1965 saw AT&T develop the first digital switch (crossing computers with the telephone switch) • Intelligent Networks - now phone companies use 2 separate networks to handle conversations (1) and signaling/connection (2) • Resulted thanks to Captain Crunch’s Blue Boxes which could rip off the phone companies – popularized by Steve Jobs and Stephen Wozniak

  15. Data Switching Technology • Packet Networks – divides data streams into small chunks, then finds the fastest route to the destination (even if it has to share a channel) • The Internet is a Packet Network • Initially this concept was developed to protect the military from electronic devastation following a nuclear attack • Evidence that this system works was seen after 9/11 • Cable Converters – The converters were once used to help antenna-based TV sets connect to cable; then came cable-ready TV sets • Now we need set-top boxes again, unless we shell out for the digital televisions

  16. Going Digital • Phone Modems – modulator-demodulator (mo-dem) convert digital pulses to tones that can be accepted by the phone system (slow at max of 56kbps) • ISDN – Integrated Services Digital Network; convert voices to digital signals within the telephone, not inside the company’s central switching office (faster at 128kbps) • Digital Subscriber Line (DSL) – phone company’s faster, high-speed internet service for video and voice over standard phone line (faster still at over 1 Mbps) • Digital Cable – uses standard coaxial cable, but can now compress 5 digital channels into 1; Here comes Video On Demand. • Cable Modems – Internet data fills same “pipe” as cable tv (more reason to switch to digital). This mode is even faster at up to 10Mbps (200x POTS!) Let’s go for a test-drive of Our system’s connection.

  17. Mobile Communication Technologies • Mobile Telephone – originally used a single central antenna and could only handle 46 simultaneous conversations in any one city • 47th caller didn’t get a dial tone—this helped stall the adoption of this technology • Pagers – act as mini radio receivers that monitor a channel multiplexed on top of an FM radio station or satellite channel • Waiting to go off until they get a specific numerical code that is unique for each number, then decodes the attached message • This also included two-way pagers (those completely annoying nextel phones) • Cellular Radio – The first cell phones transmitter analog signals along radio waves • As the user moved around, different cell towers would take over the call • These were also HUGE (eg., see any movie from the 80s)

  18. Mobile Communication Technologies • Digital Cellular – Second-generation cell phones are digital, using smaller cells and digital compression • U.S. Lags behind other developed countries • Failed to create one standard • 3rd Generation phones have internet, cameras, email and text messaging (some of you have these now) • When fully developed, we will be regularly sending full-motion video through cell phones (TV?) • Wireless Internet Options – 802.11b – G (newer) WiFi, sends packets through the air to wireless receivers at up to 10Mbps • We can use the Bluetooth protocol to interface cell phones with computers, mp3 players and cameras • LEO Satellites – Low Earth Orbit satellites will enable cheaper receivers and smaller antennas • MEO – middle earth orbit; GPS – Global Positioning System

  19. The Telecommunications Industry Players • To find out more about the industry players, look in the book on page 286. • Key ideas to note: • An Oligopoly exists within each segment (long-distance and local phone, and mobile carriers) of the infrastructure industry. • Mergers, bankruptcies and acquisitions have resulted in a powerful few • For information regarding recent legislation that impacts your rights, pay particular attention to “Big Brother is Listening” on page 295

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