Mitchell Technical Institute Telecommunications

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Mitchell Technical InstituteTelecommunications
EC 221 TV Technology

• Cable Television Network Infrastructure

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Reference

• Introduction to Telecommunications
• 2nd, Edition M.A. Rosengrant
• Chapter 22 - Handout
• Objectives
• Describe Telephony Infrastructure
• Define Outside Plant Layout
• Define Physical Infrastructure

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Infrastructure

• What is it?
• A collection of telecommunications components,
  that together provide the basic support for the
  distribution of all information within a network.

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Organization Structure

• Traditional underground cable lines are just one
  of several methods used to transmit video signals
  from the broadcaster to the home.
• Pay television companies must decide which
  transmission method or combination of methods is
  the most effective in serving their customers.
• Overall, there are four basic ways to broadcast a
  video signal

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• Terrestrial
• Coaxial/Fiber
• Microwave Multichannel
• Satellite

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Terrestrial

• a transmission tower on the ground sends a
  picture directly to a television aerial.
• This is easy to install but reception is often
  poor and only a few channels can be carried.
• This is the method traditionally used to
  broadcast network channels.

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Coaxial/Fiber

• Coaxial or fiber-optic cable TV signals travel
  through an underground cable.
• Installation is time-consuming and expensive.
• Cable is used primarily in densely populated
  urban areas.

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Microwave Multichannel

• a system that carries signals from a television
  studio to a microwave transmitter, which then
  relays them to rooftop receivers on buildings.
• These receivers are relatively small dishes that
  are easy to install and maintain.
• Microwave transmission is a low-cost alternative
  to cabling and is feasible in areas where there
  are large distances between transmitting stations
  and subscribers.

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Satellite

• A broadcaster uplinks a signal to a transponder
  on a satellite, which retransmits either to home
  dishes or to a satellite master dish (SMATV) .
• Satellite transmission is common in remote rural
  areas.
• Subscribers pay hook-up and access fees to the
  satellite owners.

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Revenue Streams

• Cable television operators rely primarily on four
  revenue streams
• Advertising
• Installation services
• Basic cable subscriptions
• Premium channel subscriptions.
• In 2002, the industry earned 49.4 billion in
  subscriber revenues and 14.7 billion in
  advertising revenues.

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Cable Regulation

• The cable industry is highly regulated by the
  U.S. government.
• Regulations affect cable system ownership, rate
  structures, channel limits, types of programming,
  and permission to access programming.
• This involvement is due to the high fixed
  investment in installation, the fact that the
  industry lends itself to being a natural monopoly
  with limited competition, and the sensitive
  nature and importance to national security of
  communications technology.

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FCC

• The Federal Communications Commission (FCC), the
  government agency empowered to regulate cable TV
  companies.
• A change in regulation has opened the door for
  cable television operators to offer telephone and
  data services.

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Telecommunications Act 1996

• The first major overhaul of United States
  telecommunications law in nearly 62 years.
• Amending the Communications Act of 1934, and
  leading to media consolidation.
• Signed into law on February 8, 1996 by President
  Bill Clinton.
• Divided into 7 Titles.

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Title I

• Entitled Telecommunications Service, outlines
  the general duties of telecommunication carriers,
  the obligations of all local exchange carriers,
  and the additional obligations of incumbent local
  exchange carriers.

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Title II

• Entitled Broadcast Services, outlines the
  granting and licensing of broadcast spectrum by
  the government.
• Including a provision to issue licenses to
  current television stations to commence digital
  television broadcasting.
• The process of renewing broadcast licenses.
• Restrictions on over-the-air reception devices.

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Title III

• Entitled Cable Services, outlines the cable
  services provided by telephone companies.
• Regulation of telecommunication services, video
  programming accessibility, competitive
  availability of navigation devices, and video
  programming accessibility.

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Title IV

• Entitled Regulatory Reform, outlines regulatory
  tolerance, a biennial review of regulations,
  regulatory relief, and the elimination of
  unnecessary Commission regulations and functions.

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Title V

• Entitled Obscenity and Violence, outlines
  regulations regarding obscene programming on
  cable television, the cable operators' refusal to
  carry certain programs, coercion and enticement
  of minors, and online family empowerment.
• Title V also gives a clarification of the current
  laws regarding communication of obscene materials
  through the use of a computer.

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Title VI

• Entitled Effect on Other Laws, outlines the
  applicability of consent decrees and other laws
  and the preemption of local taxation with respect
  to direct-to-home sales.
• Consent decrees judicial ruling expressing a
  voluntary agreement between parties to a
  subscription, an agreement between the subscriber
  and the cable operator.

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Title VII

• Entitled Miscellaneous Provisions, outlines
  provisions relating to the prevention of unfair
  billing practices for information or services.

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The ACT

• Both deregulated and created new regulations.
• Congress forced local telephone companies to
  share their lines with competitors at regulated
  rates.
• This led to the creation of a new group of
  telephone companies, "Competitive Local Exchange
  Carriers" (CLECs) that compete with ("ILECs" or
  Incumbent Local Exchange Carriers).

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Typical CATV Head-End

• Head-End Office provides TV to its subscribers.
• Video feeds received via Satellite.
• Fed into a Receiver.
• Passed to a Video switch.
• Switches various signals to modulators.
• Modulators modulate signal into specific
  frequencies.

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• The specific frequencies are fed into a computer
  that combines the signals onto 1 trunk.
• Trunks feeds signal throughout network.
• Delivering it to the Subscribers TV.

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Head-End Example
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Cable Network Divided into 4 Categories

• Head-End Office
• Trunking Cable
• Feeder Cable
• User Drops

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Head-End Office

• Cable TV location where the video signals are fed
  downstream to the user.
• The Satellite feed is located at the Head-End
  office.
• Inside the Head-End office the receivers accept
  the video coming in from the off-air antennas,
  microwave antennas and the satellite dishes.

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• From the receivers, the signals are passed to a
  video switch used to switch various signals to
  the modulator.
• The signals are then modulated onto specific
  frequencies that are fed into combining
  equipment.
• The combining equipment combines all the signals
  onto 1 pipe 1 transmission medium.
• It is then transmitted out on trunk cable.

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Trunk Cable

• Cables that carry the signal from the head end to
  groups of subscribers.
• In a CATV system, the transmission cable from the
  head end (signal pickup) to the trunk amplifier.
• Cable constructed with more than four optical
  fibers.
• Trunk Cable typically refers to a copper twisted
  pair backbone or vertical riser cable consisting
  of multiple groups of 25 pairs.

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Feeder Cables

• Coaxial/Fiber cables that run along streets
  within the served area and connects between the
  individual taps which serve the customer drops.

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Users Drop

• Location where service is handed over to the
  subscriber.
• The subscriber drop comes of the feeder cable at
  the tap point.
• The cable signal travels from the head end office
  past all subscribers.

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New Cable TV Network

• The one way transmission scheme is no longer a
  viable solution.
• High speed communication is the standard, both
  downstream and upstream.
• Old analog equipment replaced with new digital
  fiber optic equipment.
• Fiber cable is the standard to replace coaxial
  trunking and feeder cable.

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• Fiber allows for additional bandwidth.
• Efficient two way transmissions.
• Elimination of line amplifiers.
• Channelized pipe allowing system segmentation
  voice- video data.
• New Fiber Optic Digital Network is called
• Hybrid fiber/coax network (HFC).
• Dramatic change to replace old equipment.

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New terms on network

• CMTS Cable Modem Termination System.
• Equipment placed in a CATV network to manipulate
  and route signals to designated end points.
• Internet connections and standards DOCSIS
• Data Over Cable Service Interface Specification.

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SONET Mux

• Synchronous Optical NETwork Multiplexer.
• This replaced the analog to digital conversion,
  combiner equipment in the Head-End office.

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FTTC

• Fiber To The Curb
• Fiber is the transmission medium out of the
  Head-End office.
• Terminates at the HFC terminal.
• HFC terminal contains a fiber mux to convert
  signal back to electrical and sent to the end
  user via coaxial cable.

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FTTH

• Fiber To The Home
• Instead of terminating at the curb, it is
  terminated at the Home.
• Thus, eliminating coax up to the users home.
• The fiber mux is in a box at the home and handed
  over to the subscriber.

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Traditional Network Differences

• CATV and Telephone network are different in two
  fundamental ways.
• The telephone network is logically a star.
• The CATV network is logically a bus.

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Class 5 Switch

• CATV providers deploy a phone system to add
  services to the package.
• Class 5 switch, in United States telephony
  jargon, refers to a telephone switch directly
  serving subscribers.
• Class 5 switch services include basic dial-tone,
  calling features, and additional digital and data
  services to subscribers using the local loop.

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Switch Class Over View

• Class 1 exchanges - international gateways -
  handing off and receiving traffic from outside
  the USA and Canadian networks. - Legacy
• Class 2 exchanges - tandem exchanges which
  interconnected whole regions of the ATT network.
  - Legacy

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• Class 3 exchanges were tandem exchanges
  connecting major population centers within
  particular region of the ATT network. - Legacy
• Class 4 exchanges - tandem exchanges connecting
  the various areas of a city or towns in a region.
• Class 5 exchanges - those to which subscribers
  and end-users telephone lines would connect.

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Direct Broadcast Satellite

• Direct broadcast satellite (DBS) refers to
  satellite television (TV) systems in which the
  subscribers, or end users, receive signals
  directly from geostationary satellites.
• Signals are broadcast in digital format at
  microwave frequencies.
• DBS is the descendant of direct-to-home (DTH)
  satellite services.

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Geostationary Satellite

• An earth-orbiting satellite, placed at an
  altitude of approximately 35,800 kilometers
  (22,300 miles) directly over the equator
• Revolves in the same direction the earth rotates
  (west to east).
• At this altitude, one orbit takes 24 hours, the
  same length of time as the earth requires to
  rotate once on its axis.
• The term geostationary comes from the fact that
  such a satellite appears nearly stationary in the
  sky as seen by a ground-based observer

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DBS Subscriber Installation

• Consists of a dish antenna two to three feet (60
  to 90 centimeters) in diameter
• A TV set
• A signal converter placed next to the TV set, and
  a length of coaxial cable between the dish and
  the converter.
• The dish intercepts microwave signals directly
  from the satellite.
• The converter produces output that can be viewed
  on the TV receiver.

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Current Conditions

• Cable Television industry has proven to be very
  resilient.
• The industry has successfully responded to
  recession, regulation and deregulation.
• Cable industry is leading the way with new
  technologies to expand digital services.

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Industry Leaders

• Comcast Corporation
• Time Warner Cable
• Charter Communications
• Cox Communications
• Direct Broadcast Satellite Companies DirecTV
  Inc and EchoStar Communications Corp.

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Summary

• Focused on Cable Television Network
• How network has grown
• Methods used to carry signals
• Questions?