Lecture 2

• Data Communication


  Process of exchanging data between two devices
• Data Communication System/Network


  • Combination of Hardware (Physical Devices) and Software (Programs)
• Data Communication Model


  1. Sources/Sender

  2. Transmitter

  3. Transmission System/Medium

  4. Receiver

  5. Destination

  
• Sources/Sender


  Devices that generate the data to be transmitted

  
• Transmitter


  Transforms and executes the information to produce electromagnetic signals for transmission
• Transmission System/Medium


  Single transmission line or complex network connecting source to destination
• Receiver


  Accepts the signal from transmission system and converts it to a form the destination device can handle

  
• Destination


  Device that takes incoming data from receiver
• Data Communication Diagram


  • shanon weaver mathematical model

  
• Shannon-Weaver Mathematical Model


  • Involves information source, transmitter, channel -noise source, receiver and destination
• Characteristics of Data Communication

  • Message
  • Sender
  • Receiver
  • Transmission Medium
  • Protocols

  
• Data Communication Representation


  • Text
  • Number
  • Images
  • Audio
  • Video

  
• Text and Numbers


  Represented as bit patterns - a sequence of 0s and 1s
• Images


  Represented as bit patterns assigned to each pixel, with colours measured by intensity
• Audio


  Referring to broadcasting or recording of sound or music, as a continuous signal
• Video


  Referring to broadcasting or recording of pictures or movies, as a continuous signal or combination of discrete entities
• Data Communication Flow


  • Simplex
  • Half-Duplex
  • Full-Duplex
• Simplex


  Unidirectional, one device transmits and one device receives
• Half-Duplex


  Both devices can transmit and receive, but not at the same time
• Full-Duplex


  Both devices can transmit and receive at the same time
• Data communication diagram

  Data communication model