Week 2: Data Communication

On week 2, we learnt about data communication.

Data Communication:

• takes place between two devices that are directly connected by some form of point-to-point transmission medium.

• transmitted via mediums such as wires, coaxial cables, fibre optic, or radiated electromagnetic waves such as broadcast radio, infrared light, microwaves, and satellites.

Data Transmission

A. Type of Signals

   1. Analog signal

•  represent data with continuous wave

   2. Digital signal

• data represented by only two discrete states: 0 and 1 

B. Transmission Type

1. Parallel transmission: message sent one byte at a time- each bit in the byte taking separate path
2. Serial transmission: data sent one bit at a time- one after another along a single path

   Reconstruction of data after transmitted in serial
   -Synchronous and asynchronous transmission

   -Isochronous transmission
     -data sent at the same time- support some real time applications
     -initial communication between both devices to determine factors needed for data transmission

C. Direction of Transmission

  1. Simplex transmission

• one direction only
• role of transmitter and receiver fixed
• e.g: radio signal

  2. Half-duplex transmission

• 2 direction but not at the same time
• one transmits data to other without interruption
• e.g: walkie-talkie

  3. Full duplex transmission

• transmits data in both direction at the same time
• e.g: telephone

D. Data Compression