Thursday, 26 April 2012

Cabling used in Telecommunication & Networking

Wednesday, 25th April 2012
Today I was able to understand the whole lesson because it was related to something that I am able to see and imagine. Unlike previous lesson, I faced hard to understand the meaning of networking terminologies. Besides, I felt great that I had printed out the notes before our class started. I felt easier to understand Dr. Dayang’s teaching when I have the notes to refer.
So, today’s lesson was CABLING.
Cables are everywhere in our life. However, these cables are those that use in networking and we rarely notice them unless when we face networking technical problem.
Let’s start our discoveries…!!
Cabling is a type of transmission media. It is classified into two main groups – Bounded / Guided and Unbounded / Unguided.



From the above table, we notice that there are several examples of bounded media. So, next I will share about the information on these cable. 
 
a.) Twisted-pair cable can be classified into Unshielded Twisted Pair and Shielded Twisted Pair

       Unshielded Twisted Pair (UTP)
-    4 pairs of wires
-    Each is twisted with different number of twists per inch ( help eliminate interference from adjacent pairs)
-     Standard Connector to connect UTP : RJ-45 connector
-     eg. Telephone line
-     Categories of UTP :
~ Category 1 is used for voice transmission especially telephone wire
~ Category 2 is used for data transmission up to 4 Mbps (suitable for LocalTalk protocol)
~ Category 3 is used for data transmission up to 10 Mbps (suitable for Ethernet)
~ Category 4 is used for data transmission up to 16 Mbps (suitable for Token Ring)
~ Category 5 is used for data transmission up to 100 Mbps.
(* Most school use category 3 and 5. Category 5 enables fast data transmission although it is used for sharing hotspot. As for category 4, it will slow down after sharing hotspot.)

* Unshielded Twisted Pair Cable (notice that there are different number of twists per inch)

* Cross section of UTP Cable

 Shielded Twisted Pair
-          Difference with UTP:
~ 4 pairs of wires but each of them is shielded with metal shield (to prevent electromagnetic noise; thus, it looks bulky) 



* STP Cable

* Cross section of STP Cable


b.)   Co-Axial Cable
-   Different from twisted; it only has one single copper conductor at the center.
-  Conductor is surrounded by plastic insulator to separate it from the braided metal shield (to prevent electromagnetic noise and as 2nd conductor to complete the circuit.)
- Common connector used : Bayonet-Neill-Concelman (BNC) connector with different adapters (eg. T-connector)
-    Uniqueness : Suitable to use for circumstances with fluorescent lights, motors, and other computers.

* Co-axial Cable

* BNC

* T-BNC (BNC with T-connector)







Here is a video on how the BNC is connected to the Co-axial Cable.


                       video

c.)    Fiber Optics
-  Consists of a single glass core at the center surrounded by several layer of protective materials.
-   Difference with Twisted Pair and Coaxial:
~ Data transmit through light; thus, it eliminates electrical interference.
~ Able to transmit data through a longer distance.

* Fiber Optic Cable (Notice that there is light transmit through the glass core)
 

At the end of the lesson, we learned about the specific terms for cabling. The table below shows the suitable cable used in Internet with different specification. 


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