Monday, 7 September 2015

Tutorial : Communication Media

What is communication media?

 Communication media is the term used for the delivering and receiving data or information.
 Two forms of communication media:

              Analog telecommunications
       Examples: radio, telephonic and television broadcasts.

         Digital telecommunications
       Example: Computer networking and telegraphy.

Data communication media includes:

    Coaxial cable is a type of cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield.



     Advantages:

o   Has a higher bandwidth than twisted pairs (400-600mHz).
o   Less vulnerable to interference compared to the twisted pair.

     Disadvantages:

o   Can be tapped easily.
o   It has a high attenuation rate which means there is a huge reduction in the strength of the signal over a distance. This means that when used over long distances it can become costly.
o   It is quite bulky.

Where it is used today? 

Computers/Tv’s/Video Game systems – no security is needed and it only has to be used over short distances while still having a faster than average bandwidth.


       Communication Satellites is a satellite placed in orbit around the earth to relay television, radio, and telephone signals.


     Advantages:

o   Mobile communication is easily achieved because of its flexibility to interconnect mobile vehicles.
o   The quality of the transmitted signals is better than a fibre cable as the sending and receiving of information is independent on the distance.
o   Satellite relay is wide area broadcast where point to multi-point communication is possible.

     Disadvantages:

o   Time delay which reduces the efficiency of satellites in data transmission and long file transfer.
o   Overcrowding of available bandwidth due to the low of antenna gains.
o   High atmosphere losses, above 30GHz, limits the carrier frequency.

   Fibre optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves.



          Advantages:

o   They are not affected by EMI and RFI which means essentially the signal loss is much lower than other mediums like copper wiring. This also means that data can travel longer distances before signal regeneration is needed i.e. 200 km’s compared to copper cables which can only cover up to 5 km’s.
o   Optical signals can carry a lot more data than normal electrical signals. For instance optical fibers have a bandwidth of up to 2 gigabytes per second.
o   Fiber optic is also a lot safer because it can’t be hacked as easily as other mediums in terms of tapping because data isn’t sent electronically it is sent using light signals.

Disadvantages:

o   The only downside to fiber optic cables is the fact that it costs a lot more than general copper cables.
o   Another disadvantage is that fiber optic cables can’t be blended too much otherwise they’d lose some light reflecting properties,
o   Fiber optic cables can also be damaged easier than copper cables and also cost a lot to be repaired.
o   Installation has to be done by highly skilled installers with special tools.

Where it is used today?

Military- used for missile launches and radar system because a lot of heavy copper wiring can be replaced by a single pen sized fiber optic cable while still being able to withstand harsh environments and providing more security.


    Microwave transmission is the process of transmitting information or energy by microwaves. 


   Advantages:

o   Relatively low costs.
o   Able to transmit large quantities of data due to high operating frequencies.
o   Wide bandwidth.

    Disadvantages:

o   Signals do not pass through objects.
o   Affected by any interference that degrades, obstructs or interrupts the performance of microwave signals.

Where it is used today?

 Radio repeater, transmitter station, wireless energy transfer.

Twisted pairs:

      Advantages:

o    It is Cheap and easily available.
o   The cables are flexible and light
o   A specialist doesn’t need to be brought in because it can be easily installed.

      Disadvantages:

o   Vulnerable to interference and noise.
o   For analog, repeaters are needed for every 5-6 km
o   For digital, repeaters are needed every 2-3km.
o   Bandwidth is much lower than fiber or other mediums (300Hz).

Where it is used today?

 Telephone, CATV, 1000BASE-TX in the same cable and 40GBASE-T Ethernet.

When it comes to communication media another important aspect is choosing the right type of cable to send and receive information. Different cables offer different bandwidth, sizes and costs. The aim is to choose a cable that is the most beneficial and cost effective.

Some factors to consider are:

  • Cost: you need to think about how much you are willing to spend and the repercussions for instance paying extra now for fiber optic could mean it is less expensive in the future when it comes to maintenance or someone trying to hack into the cables.

  • Security: you need to think about security concerns when choosing a type of cable for instance if the data being sent and received isn’t sensitive then a medium like a coaxial cable can be used but if the data is sensitive then a safer alternative needs to be used like fiber optic which is highly secure because it is harder to tap.

  • Design for Future: you need to think about the future when dealing which communication media so you need to think about using a cable that can support a higher bandwidth then the bare minimum so if more is expected you don’t have to pay for additional installations.

The Video below shows how communications media works hand-in-hand with networking:




      If you have any further questions, please comment below and let us know. Also if you liked this tutorial or even found it useful, comment below and give us feedback! Share this with your friends as well.

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