Shielded Twisted Pair (STP)


Shielded twisted pair (STP) provides extra protection against interference and crosstalk.

  • often used for 10G Ethernet and higher within datacenter networks because it is more reliable than UTP
  • Shielding may also be a requirement in environments with high levels of external interference
    • such as cable that must be run in proximity to fluorescent lighting, power lines, motors, and generators
  • referred to generically as STP
  • several types of shielding and screening exist:
    • Screened cable has one thin outer foil shield around all pairs
      • designated as screened twisted pair (ScTP) or foiled/unshielded twisted pair (F/UTP), or just foiled twisted pair (FTP)
    • Fully shielded cabling has a braided outer screen and foil-shielded pairs
      • referred to as shielded/foiled twisted pair (S/FTP)
      • are variants with foil outer shield (F/FTP)
    • U/FTP has foil-shielded pairs but no outer shield
  • Legacy STP is complex to install
    • screening/shielding elements of shielded cable must be bonded to the connector
      • prevents the metal from acting as a large antenna and generating interference
  • modern F/UTP and S/FTP use cables, connectors, and patch panels that incorporate bonding in their design