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
