1.1.2 Product Evolution

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1.1.2 Product Evolution
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TELEPHONE
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Telegraph

• Inventor Samuel B. Morse (1837)
• Transmits messages over long distance
• Messages received are audible signals
• Earlier telegraphs experiments in Germany used
  bubbles in a glass of water

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Morse Code

• Language made up of dots and dashes in a pattern
  to represents letters and numbers
• Receiver hears short audible signals for dots and
  long audible signals for dashes

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Telephone

• Inventor Alexander Graham Bell (1870s)
• Microphone converts sound waves into electrical
  signals
• Earphone converts electrical waves into sound
  waves

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Landlines

• Plain Old Telephone Service (Post Office
  Telephone System) - POTS
• 2-twisted wire path of bi-directional, full
  duplex, voiceband
• avoids electromagnetic interference cross talk
• Frequency 300 to 3400 Hz
• Subscriber Loop
• 40 volts DC and 300 ohms
• From central office to subscribers home
• Analog lines carries control and audio signals

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Landline Telephones

• Hand Cranked Magneto Generator
• Direct connection to an operator that will
  connect the call

• Candlestick
• Direct connection to an operator that will
  connect the call
• Constantly powered

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Rotary Dial Telephone

• Rotary movements sends electrical pulses
  length represents a number
• Pulse dialing sounds like a series of clicks

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DTMF Telephone

• Dual-Tone Multi-Frequency
• Touch Tone dialing over analog lines
• An established tones frequency with distinct
  sine waves represents a number or symbol ( or )

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Analog Signals Digital Signals

• Analog Signals

• Large signal fluctuations
• any continuous signal for which the time varying
  feature (variable) of the signal is a
  representation of some other time varying
  quantity

• Digital Signals

• Small signal fluctuations
• each point in time, the value of the signal must
  be above or below some discrete threshold
• Not subject to electronic noise

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Cordless Telephone

• Uses and RF (radio frequency signal)
• Handset communicates with base station
• Handset contains rechargeable batteries

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Cellular

• RF digital signals
• Sites are spaced apart in hexagonal pattern with
  120 degree directional antennas
• CDMA (Code Division Multiple Access) encoding
  signals
• Alcalet-Lucents Lightradio, size of Rubix Cube,
  has same technology and power as a large cell
  tower

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Cellular Telephone

• Transmits and receives signals over a radio link
• Connects to cellular network and public telephone
  network

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Satellite Telephone

• Geosynchronous Satellites (4 at 22,000 miles)
• Fixed orbital position
• Transmits and receives RF digital signals

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Mobile Computing(Smartphone)

• A.K.A Personal Digital Assistant (PDA)
• Contains a Mobile Operating System
• iOS
• Android (Linux)
• Windows
• Blackberry

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TELEPHONE FUTURE
Video Apple's iPhone Concept
Video Sixth Sense Technology
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References

• "Telephone - Wikipedia, the free encyclopedia."
  Wikipedia, the free encyclopedia. N.p., n.d. Web.
  24 May 2012. lthttp//en.wikipedia.org/wiki/Telepho
  negt.

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