twisted pair (redirected from TP cable)

A thin-diameter wire (22 to 26 gauge) commonly used for telephone and network cabling. The wires are twisted around each other to minimize interference from other twisted pairs in the cable (Alexander Graham Bell invented this and was awarded a patent for it in 1881). Twisted pairs have less bandwidth than coaxial cable or optical fiber.

UTP, STP, ScTP, FTP
Twisted pair cables are available unshielded (UTP) or shielded (STP), with UTP being the most common. STP is used in noisy environments where the shield around each of the wire pairs, plus an overall shield, protects against excessive electromagnetic interference. A variation of STP, known as ScTP for "screened twisted pair" or FTP for "foil twisted pair," uses only the overall shield and provides more protection than UTP, but not as much as STP.

Standed and Solid
Both UTP and STP come in stranded and solid wire varieties. The stranded wire is the most common and is also very flexible for bending around corners. Solid wire cable has less attenuation and can span longer distances, but is less flexible than stranded wire and cannot be repeatedly bent. Following are the twisted pair categories.

                      Application
                      MHz=bandwidth
 Cat  Cable type      Mbps/Gbps=maximum data rate
  1   UTP             Analog voice
  2   UTP             Digital voice up to 1 Mbps
  3   UTP, ScTP, STP   16 MHz,   4 Mbps
  4   UTP, ScTP, STP   20 MHz,  16 Mbps
  5   UTP, ScTP, STP  100 MHz, 100 Mbps
  5e  UTP, ScTP, STP  100 MHz,   1 Gbps
  6   UTP, ScTP, STP  200 MHz,  10 Gbps
  7   STP, ScTP       600 MHz

Shielded and Unshielded Twisted Pairs

The metal shrouds on shielded cable add protection against external interference.

The Twisted Pair

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(hardware)

twisted pair - A type of cable in which pairs of conductors are twisted together to randomise possible cross-talk from nearby wiring. Inadequate twisting is detectable using modern cable testing instruments.