Home  ›  11th Syllabus  ›  Transmission Media Guided Media  ›  Unit 202

Transmission Media Guided Media

, ,

Transmission media

Transmission media are of two types 
  • Guided or Bounded media 
  • Unguided or Unbounded media 
Guided or bounded media- includes cables for transmission of data. Some examples of guided or bounded media are twisted pair cable, coaxial cable and optical fibre cable

Unguided or Unbounded media- includes waves through air water or vacuum for transmission of data. Some examples of unguided media are microwave, radio wave, infrared, laser

Guided or Bounded media

Twisted pair cable

Twisted pair cable is an ordinary copper wire that connects many business computers and home computers to the ISP (Internet Service Provider). To reduce crosstalk or electromagnetic induction between pair of wires two insulated copper wires are twisted around each other. Each connection on twisted pair requires both wires
Advantages of twisted pair cable
  • It is easy to install and maintain 
  • It is physically flexible
  • It has a low weight 
  • It is very inexpensive 

Disadvantages of twisted pair cable
  • It is incapable of carrying a signal over long distances without the use of repeaters
  • It is not suitable for broadband applications due to low bandwidth capability
  • It supports maximum data rates 1 Mbps to 10 Mbps
Coaxial cable

Coaxial cable are a type of cable that is common for data communication and used by cable TV. In this type of wire single centre core is surrounded by dielectric insulator and then dielectric insulator is covered with metallic shield and then a plastic jacket cover metallic shield. Data is transmitted through centre core and metallic shield serve as a line to the ground.
Advantages of coaxial cables 
  • Data transmission of coaxial cables are better than twisted pair cables 
  • Coaxial cables can be used for broadband transmission
  • Offers moderately higher bandwidth upto 100 Mbps to 400 Mbps 
Disadvantages of coaxial cables  
  • Expensive compared to twisted pair cables
  • Coaxial cables are not compatible with twisted pair cable

Optical fibre cable 

Optical fibre cable is a cable containing one or more optical fibres that are used to carry light. In this type of cable optical fibres are coated with plastic layers and contained in a proactive tube. And these are used for high speed data connection. Now optical fibre cable is made up of glass or plastic and transmit signals in the form of light. 
Advantages of optical fibre cables 
  • It is immune (safe) to electrical and magnetic interfaces
  • Highly suitable for harsh industrial environment 
  • It provide secure transmission with very high transmission speed
  • It is capable of broadband transmission and also possible to mix data transmission channels with channels for telescope, graphics, TV and sounds 
Disadvantages of optical fibre cables 
  • Installation problem because fibre opticals are quite fragile and may need special care 
  • Connecting two fibres together or a light source to a fibre connection is difficult process 
  • Connection losses are common problems 
  • Fibre optical cables are more difficult to solder 
  • Most expensive of all the cables

Subscribe to: Post Comments ( Atom )