Unshielded Twisted Pair (UTP)

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The most popular type of network cable is of a copper wire construction called unshielded twisted pair (UTP).

• used in telephone networks and data networks extensively
• made up of four copper conductor wire pairs
• one pair of insulted wires twisted together forms a balanced pair
  • pair carries the same signal but with different polarity
    • one is positive
    • one is negative
    • allows receiver to distinguish signal from noise (interference) better
• pairs are twisted at different rates
  • reduces external interference and crosstalk
  • crosstalk is whereby one pair causes interference in another due to their proximity
• has an insulated outer jacket
• the electrical signaling method is only reliable over limited range
  • signal suffers from attenuation
    • loses strength over long ranges
  • Most UTP cable segments have a maximum distance of 100 m (328 feet)
• most twisted pair cable used in office networks is unshielded twisted pair (UTP)
  • buildings are often flood wired
    • involves cables being laid to every location in the building that may need a telephone or computer
• copper wire thickness is measured using American Wire Gauge (AWG)
  • increasing AWG numbers represent thinner wire

Types of Conductor Wires

• two types of conductor wires:
  • solid cabling uses a single thick wire per conductor
    • used for cables that run behind walls or through ducts
    • uses thicker 22 to 24 AWG
    • lower attenuation
  • stranded cabling uses thin filament wires wrapped around one another
    • used to make flexible patch cords
    • usually 26 AWG
    • higher attenuation, so poor for more than 5 m in length