RECOMMENDED READING
      From textbooks:
          Page 103-111 of Data Communications: From 
            Basics to Broadband, 3rd Edition by William J. 
            Beyda (ISBN: 0-13-096139-6) 
          Chapter 6 of Data Communications and 
            Networking, 3rd Edition, Behrouz A. Forouzan 
            (ISBN: 0-07-251584-8) 
    Based on
    Data Communications and Networking, 3rd EditionBehrouz A. 
    Forouzan,
    ©                                                                         2
      McGraw-Hill Companies, Inc., 2004
           DIVIDING A LINK INTO CHANNELS
      Multiplexing
          A set of techniques that allows the simultaneous transmission 
            of multiple signals across a single data link.
      Multiplexer (MUX)
          Combines multiple streams into a single stream (many to 
            one).
      Demultiplexer (DEMUX)
          Separates the stream back into its component transmission 
            (one to many) and directs them to their correct lines.
    Based on
    Data Communications and Networking, 3rd EditionBehrouz A. 
    Forouzan,
    ©                                                                          3
      McGraw-Hill Companies, Inc., 2004
             CATEGORIES OF MULTIPLEXING
    Based on
    Data Communications and Networking, 3rd EditionBehrouz A. 
    Forouzan,
    ©                                                                         4
      McGraw-Hill Companies, Inc., 2004
         TIME DIVISION MULTIPLEXING (TDM)
      Digital process that allows several connections to 
        share the high bandwidth of a link
      Time Slots and Frames
          Each terminal/host given a “slice” of time (time slot)
          In TDM, a frame consists of one complete cycle of time 
            slots, with one slot dedicated to each sending device.
    Based on
    Data Communications and Networking, 3rd EditionBehrouz A. 
    Forouzan,
    ©                                                                         5
      McGraw-Hill Companies, Inc., 2004
                             TDM FRAMES
       Pure TDM:  mux-to-mux speed = aggregate  terminal 
        speeds
       No loss of data (similar to voice call multiplexing)
    Based on
    Data Communications and Networking, 3rd EditionBehrouz A. 
    Forouzan,
    ©                                                                         6
      McGraw-Hill Companies, Inc., 2004