Data Communication’s third lecture review in more detail the Physical Layer (Application -> Transport -> Network ->¬†DataLink -> Physical).

Analogue vs Digital

Dataflow transmissions (Simplex, Half Duplex, Full Duplex, Multiplex)

Multiplexing Division methods:

  • Frequency Division multiplexing [FDM]
  • Time Division multiplexing [TDM]
  • Statistical Time Division Multiplexing [STDM]
  • Wavelength Division Multiplexing [WDM]

Communication Medias

Physical

    • Twisted Pair Cables
    • Coaxial Cable
    • Fiberoptic
  • Wireless
    • Radio
    • Infrared
    • Microwave
    • Satellite

Interestingly, as satellites need to orbit the earth at quite a high distance to maintain stable service (ideally geostationary appx. 36,000kms) the delay due to the speed of light makes fibre optic a much faster option.

Optical fiber is number 1 in data transmission

The concept of using amplitude, frequency and phase modulation all at once to send multiple bits per symbols was also introduced. Quadrature Amplitude Modulation is an example of this, utilizing Amplitude and Phase shifting.

The tutorial saw us again using Wireshark to get a practical view of some of the topics we had discussed in the previous lecture. The TCP/IP packets were under review most of which made intuitive sense.