Standard Cat5e & Cat6 Network Cabling Structure

A standard Network Patch Cable such as Cat5e and Cat6 has eight individual stranded or solid copper wires, with an additional ground or drain wire. Each individual wire is grouped together into what’s called a “Pair”. A Pair is two wires are twists together in a spiral format, which helps reduce Electromagnetic Interference (EMI). EMI is caused by outside disturbances that interrupt, obstruct, or limit the effectiveness of the cable’s performance. EMI is commonly caused by crosstalk of other electrical devices. There are three different types of Crosstalk:

Crosstalk Types:

1. Near End Crosstalk (NEXT) is interference between two pairs in a cable measured at the same end of the cable as the transmitter.
2. Far end crosstalk (FEXT) is interference between two pairs of a cable measured at the other end of the cable from the transmitter.
3. Alien crosstalk (AXT) is interference caused by other cables routed close to the cable of interest.

The most common Ethernet Network Cable and Telephone System Cables are Unshielded Twisted Pairs (UTP). Unshielded Twisted Pairs (UTP) has no metal shielding of any kind, UTP’s only protection from EMI is its internal structure with its twisted pairs. To help reduce additional EMI or Crosstalk, there are different types of shielding options. A shielded cable has a thin metal shield that acts as a protectant against outside electrical interferences. The standard shielding formats for the Cat5e and Cat6 Patch Cables can exist in three different formats.

Shielding Formats:

·         Foiled Twisted Pairs (FTP):  foiled shielding surrounds all four pairs.

·         Shielded Twisted Pairs (STP): each individual pair is wrapped in their own personal shield

·         Shielded Foiled Twisted Pairs (SFTP of S/STP): foiled shielding surrounds all four pairs and each individual pair is wrapped in their own personal shield

The most basic of the shielding formats is the Foiled Twisted Pairs (FTP). The FTP has a thin layer of metal foiling, under that jacket that encases all four pairs. The Shielded Twisted Pairs (STP) differs from the FTP, instead of one larger foil shield there are four separate smaller shields. In the STP format each individual pair is wrapped in a protective foil increasing the cables resistance to EMI ever more. The last shielded format and most protective against the three different crosstalks is Shielded Foiled Twisted Pairs (SFTP or S/STP). The SFTP or S/STP has both the benefits of the FTP and STP formats. The SFTP or S/STP format has the outside foiling protection around the four pairs similar to the FTP format, but in addition, each individual pair is also individually wrapped. SFTP or S/STP is also commonly referred to as Double Shielding.

• UTP (Unshielded Twisted Pairs)

• FTP (Foiled Twisted Pairs)
• STP (Shielded Twisted Pairs)

• SFTP or S/STP (Shielded Foiled Twisted Pairs)

It is very important that EMI is taken into account when choosing between the different Cat5e and Cat6 formats. The cable is going in a low EMI application then UTP is the most economical choice because the EMI or Crosstalk will not greatly affect the performance of your cables. The structure of the Cat5e and Cat6 Network Patch Cable is designed to reduce EMI and crosstalk for your most basic applications (internet connection, etc). For applications that are subjected to abundant crosstalk interference, it is vital to select a shielding that will correctly optimize the cables performance.

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