Data Communication

So soon that it's already my second official lecture XD

I have been blogging for quite some years but never ever blog in such a way of summarising class harvest week in and week out.

Guess what? I'm gradually falling in love with the making of this very personal learning trace :）

What I write is just all what I stand for and belong to in terms of knowledge.

This awesome week, we learnt about Data Communication.

It's about：

collection and distribution 

  of the  

  electronic information （What)

  from & to  

  remote facilities （Where)

  by means of

electrical transmission system.(How)

Data can appear in a variety of styles...

Be it TEXT

Be it STILL PICTURE

Be it ANIMATED GRAPHIC

Or even VIDEO

All these types of raw data must be digitized ( converted into signal that can be understood by the communication media ).

There are 2 forms of signal which can be converted into.

1. Analogue signal

* Formed by continuously varying voltage levels that create a wave

* Represented by characteristic sine wave.

*Frequency is the number of oscillations or wavelength cycles per second. It is measured in Hertz (Hz).

*Amplitude = Wave's height (V)/ decibel (dB) 

2. Digital signal 

* Transmission of binary electrical/ light pulses that only have to state 0 & 1.

* Need to be changed into analogue signal to be transmitted through PSTN line.

The process of changing...

 The hardware used in a computer to perform this process is the MoDem.

There are 2 types of data transmission mode:

1. Parallel transmission, where a group of bits is transmitted simultaneously by using a separate line for each bit.

 like a supermarket having a number of cashier counters to serve groups of customer separately at the same time 

XD

2. Serial transmission transmits all the bits one after one another on a single line.

similar to... a single long queue !

Next, we'll take a look on Data Flow

There are 3 operation styles :

1. Simplex 
- Data is transmitted in one direction.
- The role of transmitter and receiver are fixed.
- eg: radio station, Television

2. Half-duplex 
- Message can flow in two direction.
- The role of transmitter and receiver can be exchanged.
- eg: walkie-talkie
- Better than simplex

3. Full-duplex
- Consists of 2 simplex channel
- Both station can transmit and receive simultaneously
- eg: onlie chatting, phone call

Multiplexing 

* a set of techniques that enable more than one device to combine and send their signals simultaneously through a single data link.

* Networks can transfer several types of information. Each type uses a different method.

* The latest technology of the link includes high-bandwith media eg coaxial cable, optical fibre and terrestrial and satellite microwaves.

* Each of the links has an adequate carrying capacity. When two or more devices share the same link, it will be cost-effective.

My little reflection of the day:

Have learnt the importance of being pro-active without having to wait for briefing and instruction all the time, as the only one in the class who emailed her blog url to Dr.Dayang, Sara managed to get full mark for the first class entry  due to her willing to take initiative ;)


A thousand miles of journey begins with a single step. So why afraid of taking the first move? 


We always wait for the right moment with the right self at the right place to do the right thing.


But realise it or not? We're living in a world which is elapsing..there's only RIGHT NOW.