Mar 9, 2012

Reflection #2

Greetings, future teachers!

This week, Dr. Dayang is getting us into the topic about data communication. In a world where we are about to set off in a brisk pace, changing data in a faster way in quite a convenience. That is why we need the access of data communication. Data communication is the collection and distribution of the electronic representation of information from and to remote facilities by means of electrical transmission system.

Among all the data, the data in form of text, voice and still pictures are known as RAW DATA or RAW INFORMATION and they must be digitized to be transmitted through computer. The raw data need to be convert into signal so it can be understood by the communication media as for the data to be transmitted.
Here, there are two forms of signal which are analogue signal and digital signal.

The differences between analogue signals and digital signals.

These two signals will carry out two process on conversion:
  • Analogue to digital = modulation
  • Digital to analogue = demodulation

To make it simple, the conversion of analogue to digital is merely because digital signal is the language of the computer. Here is one example of these two conversion:

The conversion that occurs between a microphone and a speaker.

The hardware that is used in computer to do this process is called MODEM as the combination of the word modulation and demodulation.

Let's move on to the data transmission mode, shall we? There are two types of transmission :

Parallel transmission and Serial transmission

By looking at this figure, I am sure that you can already guess the meaning of both transmission, right?

Bits, or binary digits consists of Byte, Kilo, Mega, Giga and Tera. One bytes is equal to 8 bits.

Based on the figure above, the serial transmission is a bit slower than the parallel transmission because it obviously transmits all the bits one after another on a single line.

Under the serial transmission mode, there are two types of transmission:
  • Synchronous transmission
  • Asynchronous transmission.

The synchronous transmission is a large group of data that is transmitted in blocks called frame.

On the other hand, the asynchronous transmission is the bits that are divided into small groups in form of bytes and send independently. This means a groups of bits can be sent at any time and the receiver will never know when they will arrive.

Here are some examples:

The synchronous transmission is Now, moving on to the data flow. The process of exchanging can be done in three operation style:

  • Simplex
  • Half-duplex
  • Full-duplex

The simplex operation is when the data is transmitted in one direction only. As much as I
understand about it, the role of transmitter and receiver are fixed.

For example, when you are watching television or listening to the radio where you as the receiver only got to understand the message or information without reacting back to the sender.

The half-duplex operation is when the transmission can flow in two direction but never at the same time. The nearest example is the walkie talkie.

Last but not list, the full-duplex operation is when both station can transmit and receive the information simultaneously. it is usually consist of two simplex channel, for example the the online chatting.

As much as I concern, the lesson learned this week mostly introduced me to the information on how the network performed in the internet and from the computer. This actually make me a computer literate as I understand what is happening throughout the process of transmission and receiving the information. I hope in the next class, I can grab all the information effectively as I am quite confused when it comes to computer learning. :D

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