Networking Guide : Physical Media - Twisted Pair Cable Categories


Picture: Shielded Twisted Pair (STP)

STP (Shielded Twisted Pair) is a cable containing several twisted pairs that has individual shields, an outer shield, and an insulator. STP is more reliable than UTP. However STP is less known because it is used only in situation where there is complex cabling such as in factory building.


Picture: Screened Twisted Pair (ScTP)

ScTP (Screened Twisted Pair) is similar with STP but each twisted pair has no individual shield.

Twisted pair cable is graded based on the number of twists per inch, its cable structure and traffic carrying capacity into several categories, as follows:

Category Type Bandwidth Typical applications
Cat 1 UTP < 1 MHz telephone
Cat 2 UTP 1 MHz telephone
Cat 3 UTP, ScTP, STP 16 MHz telephone, 10BaseT, 4 Mbps Token Ring
Cat 4 UTP, ScTP, STP 20 MHz 16 Mbps Token Ring, 10BaseT
Cat 5 UTP, ScTP, STP 100 MHz 10BaseT, 100BaseT
Cat 5e UTP, ScTP, STP 350 MHz 100BaseT, 1000BaseT
Cat 6 UTP, ScTP, STP 550 MHz 1000BaseT, ATM
Cat 7 ScTP, STP 600 MHz 10 Gbps network

Table: Twisted Pair categories and their applications

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