WebTV and Other Internet Appliances

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WebTV and Other Internet Appliances

• Chapter 5

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You Will Learn

• About thin clients and the technological trends
  in devices used to access the Internet
• About Microsoft WebTV and how it can be used by
  PCs and other devices
• How Internet technology works and the different
  hardware and software devices that use the
  technology

continued
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You Will Learn

• About wireless Internet appliances, and about
  some of the concerns and challenges of these new
  technologies

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Trends in Computing

• Main frame/dumb terminal approach (1970s)
• Stand-alone PCs (1980s)
• Client/server model
• 3-tier model
• Uses client/server model with an extra layer,
  which is added by presentation software such as a
  web browser
• Thin client/fat server model

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Dumb Terminal
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3-Tier Model
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Thin Clients

• A computer that has little processing power
• Used primarily to connect to a powerful server
  (fat server) that provides applications software
  and data, and processes both
• Cost less than PCs, but lack computing power or
  total functionality of PCs

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Example of a Thin Client
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Internet Appliances

• Devices that can access the Internet and use it
  for limited applications such ase-mail and web
  surfing
• Limited in functionality work much like dumb
  terminals
• Inexpensive
• Easy to use

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WebTV and WebTV for Windows

• WebTV
• Offers Internet access using the television
• Microsoft WebTV for Windows
• Offers television viewing over the computer

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Watching TV on Your Computer
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Participating in Interactive Television
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Minimum Hardware Requirements for Watching TV on
a Computer

• Intel Pentium compatible 120 MHz processor
• 16 MB RAM
• 1 GB disk space
• Super VGA monitor
• Television tuner card with drivers to support
  WebTV for Windows
• Cable or antenna connection
• Internet connection
• Mouse with two buttons

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Recommended Hardware for Watching TV on a Computer

• Intel Pentium compatible 200 MHz processor
• 32 MB RAM
• 2 GB disk space
• 28,800 bps (or faster) modem
• Sound card
• Wireless keyboard with pointing device

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Using WebTV for Windows
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Accessing the Internet Through Your Television
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Drawbacks of WebTV

• Does not have a hard drive cannot store files or
  scan and save pictures
• Does not have Adobe Reader cannot read PDF files
• Can display only two kinds of video clips (Video
  Flash and MPEG)
• Has own browser cannot use Internet Explorer or
  Netscape Navigator
• Online chat is not available

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Requirements to Use WebTV and a TV to Access the
Internet

• Television
• Transceiver (the Internet appliance)
• Current manufacturers Philips Magnavox, Sony,
  Mitsubishi, RCA, and EchoStar
• Subscription to a WebTV service
• Phone line

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Interactive Television

• Provides interactive web sites that are related
  to specific television shows
• Vertical blanking interval (VBI) between frames
  holds the hyperlink of a web page that is
  synchronized with the TV show
• Advanced Television Enhancement Forum (ATVEF)
• Controls standards and directions of interactive
  television
• Has strong support and endorsement of Microsoft

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Interactive Television
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WebTV HTML Links

• Specific HTML tags and methods are used to
  account for relatively low resolution of TV
  screens and limited number of plug-ins that WebTV
  can support
• Examples
• BGCOLOR (background color)
• CURSOR (cursor color)

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Internet Telephony

• PC to PC
• Each PC is equipped with microphone, speakers,
  and matching software
• PC to phone
• Uses an ITSP (Internet Telephony Service
  Provider)
• Phone to phone
• Uses an ITSP at both ends

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Internet Telephony

• ITSP
• Provides access between the Internet and the
  public telephone network
• Converts data from the packet-switched Internet
  to the circuit-switched public telephone system
  (Public Switched Telephone Network or PSTN)
• Voice over IP (VoIP) protocol
• Sends voice data over the Internet

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PC-to-PC Implementation
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PC-to-PC Implementation

• Each computer is called an IP telephony terminal
  it can be used to initiate or receive voice
  communication over the Internet

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PC-to-Phone Implementation

• PC initiates the call using VoIP software

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PC-to-Phone Implementation
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PC-to-Phone Implementation
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PC-to-Phone Implementation
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Phone-to-Phone Implementation

• An Internet call is initiated from a telephone
• Requires an IP phone
• Can initiate a telephone call over the Internet
  without first involving the regular telephone
  system
• Must have a direct connection to the Internet

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Phone-to-Phone Implementation
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Example of an IP Phone
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Another Device for Phone-to-Phone Implementation
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Wireless Internet Appliances

• Wireless Internet devices
• The protocol these devices use
• Trends in wireless technology

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Wireless Devices

• Designed to get specific information from the web
• Limited to predetermined features and options
• Most are menu-driven
• Usually no choice about the ISP
• Some run software that converts HTML so it can be
  displayed (clipping)

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Using Wireless Technology to Browse the Internet
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Wireless Application Protocol (WAP)

• Communication standard designed for mobile
  Internet access
• Specifies how information from the Internet is
  formatted, transmitted, and received by wireless
  Internet appliances
• Uses Wireless Markup Language (WML)

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Limitations of Wireless Internet Devices
Addressed by WML

• Narrow bandwidths (9.6 to 14.4 kbps) and limited
  network connections
• Small display areas and limited input keys
• Limited memory

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How WML Addresses the Limitations

• Has a limited tag set
• Some tags have a different syntax when compared
  with HTML
• Organizes files in decks cards are sections of
  the deck that fit onto one screen

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Using WAP Specifications to Access the Internet

• Wireless devices use a cellular connection to
  transmit the request for data in WAP packets in a
  compressed binary format to the gateway at the
  ISP
• The gateway receives WAP packets and converts
  packets to WML (or HTML)
• The request is sent to the Internet
• Data is sent back to the gateway in either HTML
  or WML and WMLScript format

continued
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Using WAP Specifications to Access the Internet

• The gateway receives data from the Internet and
  (if necessary) clips it from HTML and converts it
  into WAP packets (compressed binary code)
• WAP packets are transmitted over the airwaves
  back to the wireless device
• Wireless devices have micro-browsers that
  interpret code and display information on the
  screen

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Using WAP Specifications to Access the Internet
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Use of Wireless Devices

• Telephones
• Pagers
• Personal digital assistants (PDAs)

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Advantages of Wireless Devices

• Small size and portability
• Instant notification or alert service
• Locator services
• Access to companys intranet over the web

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Example of a Pager
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Example of a PDA
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Chapter Summary

• Emerging trends and standards in client devices
  for accessing the Internet
• WebTV
• Internet telephony
• Wireless devices
• Thin clients
• Other Internet appliances