WIRED COMMUNICATION MEDIA

Wired communication refers to the transmission of data over a wire-based communication technology. Examples include telephone networks, cable television or internet eccess and fibre-optic communication. Also wave guide (electromagnetism), used for high-power applications, is considered as wired line. 


* TYPES OF CABLES

• Twisted Pair Cable

              
          ~ Twisted pair cable consists of two strands of insulated copper wire, twisted
             around each other. Multiple twisted pairs can be combined into a single cable.
             This twisted-pair configuration somewhat reduces  interference from
             electrical field.
          ~ The wires are twisted together to reduce noise. Noise is an electrical
             disturbance that can degrade communications.

• Coaxial Cable

               

         ~ Coaxial cable consists of a single copper wire surrounded by at least three
             layer an insulating material, braided wired, plastic coating.
         ~ Cable television (CATV) network wiring ofter uses coaxial cable because it
             can be cabled over longer distances than twisted-pair cable.
         ~ Most of today's computer networks, however, do not use coaxial cable
            because other transmission media such as fiber-optic cable transmit signals
            at faster rates.  

• Fibre Optic

                

          ~ Fibre optic cable consists of dozens or hundreds of thin strands of glass that
             use light to transmit signal. Each strand, call optical fibre, is an thin as a
             human hair.
          ~ Inside the fibre-optic cable, an insulating glass cladding and a protective
             coating surround each optic fibre.
          ~ Fibre optic cables have the following advantages over cables that use wire,
             such as twisted-pair and coaxial cables:
                     * Capability of carrying significantly more signals than wire cables
                     * Faster data transmission
                     * Less susceptible to noise (interference) from other devices such as
                        copy machine
                     * Better security for signals during transmission because they are less
                        susceptible to noise
                     * Smaller size (much thinner and lighter weight)

          ~ Disadvantages of fibre-optic cable are it costs more than twisted-pair or
             coaxial cable and can be difficult to install and modify. Despite these
             limitations, many local and long-distance telephone companies are replacing
             existing telephone lines with fibre-optic cables. Businesses also are using
             fibre-optic cables in high-traffic networks or as the backbone in a network.