TRANSMISSION MEDIA

TRANSMISSION MEDIA

1. twisted pair-cable

   • categories - classify UTP cable into seven categories based on cable quality
   • performance - can pass a wide range frequencies. The increasing frequency will increase the attenuation

2. coaxial cable

   • categories - RG rating. Each RG number denotes a unique set of physical specifications,including the wire gauge of the inner conductor, the thickness and the type of the inner insulator, the construction of the shield and the size and type of outer casting
   • connector
     • BNC connector
     • BNC-T connector
     • BNC terminator
   • performance - much higher bandwidth , the signal became weaker rapidly and requires the frequent use of repeaters

3. fiber-optic cable

   • propagation modes
     • multi mode
       • multimode step-index fiber
       • multimode graded-index fiber
     • single-mode
   • categories - defined by the ratio of diameter of their core to the diameter of their cladding, both expressed in diameter
   • connectors
     • subscriber channel (SC)
     • straight-tip (ST)
     • MT-RJ
   • advantage
     • higher bandwidth and data rate
     • less signal attenuation
     • immunity to electronic interference
     • light weight
   • disadvantage
     • not easy to install
     • hard to maintain
     • undirectional
     • more expensive

4. radio wave

   • propagate long distance in the sky mode and omnidirectional
   • propagate in all directions
   • use omnidirectional antenna

5. microwave

   • unidirectional and uses unidirectional antenna
   • type antenna
     • parabolic antenna
     • horn antenna