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twisted pair

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 in 1881. Twisted pairs support less bandwidth than coaxial cable or optical fiber.

Unshielded (UTP) and Shielded (STP)
Twisted pair cables are available unshielded (UTP) or shielded (STP), with UTP being the most common. Shielded twisted pair (STP) is used in noisy environments and protects against electromagnetic interference.

Stranded and Solid
Both UTP and STP come in stranded and solid wire varieties. Stranded is the most common and also very flexible for bending around corners. Solid wire has less attenuation and spans longer distances but is less flexible.

Shielded and Unshielded Twisted Pairs
ScTP (screened twisted pair), also called "foil twisted pair" (FTP), uses one overall shield for more protection than UTP but not as much as STP, which has shields around each wire pair.

    Cable      Band-      Data
 #  Type       Width      Rate

 1  UTP       Analog voice
 2  UTP                 1 Mbps

 3  UTP/STP   16 MHz,   4 Mbps
 4  UTP/STP   20 MHz,  16 Mbps
 5  UTP/STP  100 MHz, 100 Mbps
 5e UTP/STP  100 MHz,   1 Gbps
 6  UTP/STP  200 MHz,  10 Gbps (<10 m)
 6a UTP/STP  500 MHz,  10 Gbps (>10 m)

 7  STP      600 MHz   10 Gbps
 7a STP     1000 MHz   40 Gbps (<15 m)

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