Cables

Cables are usually the medium in which data is sent trough from each node of a communication system. They carry analogue signals which represent the data and information. There are three common types of cables which are used today to transmit data from node to node; Twisted Pair, Coaxial and Optic Fiber.

Twisted pair cables are two insulated conductors twisted together. There are two types of twisted pair: shielded twisted pair (UTP) and shielded twisted pair (STP). Shielded twisted pair has an extra layer of insulator around the twisted pair. Electrical signals are sent down the cable transmitting data.

Twisted pair is used in Ethernet cables.

Coaxial cables uses electric signals to carry data and information. It is made out of a stiff copper wire surrounded by insulating material, then encased in a conductive mesh layer and an outer layer of insulation.

Optic fiber uses light to transmit data, a beam of light is sent down the optic fiber and it carries data. It consist of an extremely thin glass fibre surrounded by cladding. It works by refraction and light travels down the fibre by total internal reflection. It is then protected with insulation.

Used for joining LANs. There are hundreds of optic fibres undersea connecting the world together.

Twisted Pair

  • Cheapest
  • Least protected from interference
  • Lowest bandwidth and speed

Coaxial

  • Moderate price
  • Protected by not immune to interference
  • Medium bandwidth and speed

Optic Fibre

  • Expensive
  • Completely free from interference
  • Highest bandwidth and speed