Views:18 Author:Site Editor Publish Time: 2019-06-17 Origin:Site
LAN CABLE Unshileded and Shielded Sorts
Twisted pair cabling is a type of wiring in which two conductors of a single circuit are twisted together for the purposes of canceling out electromagnetic interference(EMI) from extern al sources; for instance,electromagnetic radiation from unshielded twisted pair (UTP) cables, and crosstalk between neighboring pairs. It was invented by Alexander Graham Bell.
In contrast to FTP (foiled twisted pair) and STP (shielded twisted pair) cabling, UTP (unshielded twisted pair) cable is not surrounded by any shielding.It is the primary wire type for telephone usage and is very common for computer networking,especially as patch cables or temporary network connections due to the high flexibility of the cables.Twisted pair cables were invented by Alexander Graham Bell in 1881. By 1900, the entire American telephone line network was either twisted pair or open wire with transposition to guard against interference. Today, most of the millions of kilometers of twisted pairs in the world are outdoor landlines, owned by telephone companies, used for voice service,and only handled or even seen by telephone workers.
Shielded twisted pair (STP or STP-A)
150 ohm STP shielded twisted pair cable is defined by the IBM Cabling System specifications and is used with token ring or
FDDI networks.This type of shielding protects cable from external EMI from entering or exiting the cable and also protects
neighboring pairs from crosstalk.
Screened twisted pair (ScTP or F/TP)
ScTP cabling offers an overall sheath shield across all of the pairs within the 100 Ohm twisted pair cable. F/TP uses foil shielding instead of a braided screen.This type of shielding protects EMI from entering or exiting the cable.
Screened shielded twisted pair (S/STP or S/FTP)
S/STP (Screened Shielded Twisted Pair) or S/FTP (Screened Foiled Twisted Pair) cabling offer shielding between the pair sets and an overall sheath shield within the 100 Ohm twisted pair cable. This type of shielding protects EMI from entering or exiting the cable and also protects neighboring pairs from crosstalk.
Shielded foiled Twisted pair (SFTP)
SFTP is different from S/FTP, SFTP is a kind of cable which has Foil and shield together. Usually use for outdoor cables for better protection against electrical signals and physical effects.
Comparison of some old and new abbreviations, according to ISO/IEC 11801:
The code before the slash designates the shielding for the cable itself, while the code after the slash determines the shielding
for the individual pairs:
TP = twisted pair
U = unshielded
F = foil shielding
S = braided shielding