Category 5 / 5E & Cat 6 Cabling Tutorial and FAQ's

Fiber Optic Jargon Category 5 / 5E & Cat 6 Cabling Tutorial and FAQ's

The following article aims to provide beginner to intermediate-level installers with just the right mix of technical and practical information on Category 5, Category 5e, and Category 6 UTP network cabling. Please look for our upcoming tutorial on Category 6A and 10 Gigabit UTP cabling.

The information presented in this article does not cover all details necessary to complete a fully compliant TIA-568B installation that would require reading the entire standard. It does, however, touch upon what I believe to be the most important aspects you need to know. To ensure that you fully understand all of the information, I strongly suggest reading the entire article, including the definitions. Even the intermediate-level installer may discover useful facts they were previously not aware of. Please note that this article is for general information only. Always check with local code officials, and / or cabling consultants when planning a network cabling installation.

This article applies to Category 5, Category 5e (Cat 5 Enhanced), and Category 6 cables. When reference is made to UTP network cable, we are referring to all three categories. Please also be aware that the terms Category and Cat are used interchangeably throughout this article to refer to cabling types.

cables connecting
The photo above shows a typical Category-5e patch panel with patch cables connecting each network links switch (hub) ports.
connection diagram
The photo above shows the backside of a typical Category 5 patch panel. The connections here are accomplished with insulation displacing connection (IDC) 110 blocks. Note that the connection diagram shows both 568A and 568B wiring schemes.
Key Definitions
UTP (Unshielded Twisted Pair)

Used primarily for data transmission in local area networks (LANs), UTP network cable is a 4-pair, 100-ohm cable that consists of 4 unshielded twisted pairs surrounded by an outer jacket. Each pair is wound together for the purposes of canceling out noise that can interfere with the signal. UTP cabling systems are the most commonly deployed cable type in the U.S.

F/UTP (foil unshielded twisted pair)

F/UTP cable consists of four unshielded twisted pairs surrounded by an overall foil shield. F/UTP has also been referred to as ScTP (screened twisted pair) and FTP (foiled twisted pair). F/UTP cable is not as common as UTP, but is sometimes deployed in environments where electromagnetic interference (EMI) is a significant concern. With shielded systems, the foil shield must maintain continuity throughout the entire system.

S/FTP (shielded foil twisted pair)

S/FTP consists of four foil-shielded twisted pairs surrounded by an overall braided shield. This fully shielded cable is often referred to as PiMF (pairs in metal foil), or SSTP. It is the primary cable type deployed in Europe, but rarely seen in the U.S. With shielded systems, the foil shield must maintain continuity throughout the entire system.

Category 5 Cable

Category 5e cable is an enhanced version of Category 5 that adheres to more stringent standards (see comparison chart below). It is capable of transmitting data at speeds of up to 1000 Mbps (1 Gigabit per second).

568B Standard

Published in 2001, the TIA-568B standard sets minimum requirements for the various categories of cabling. The 568 "standard" is not to be confused with 568A or 568B wiring schemes, which are themselves part of the standard.

568A & 568B Wiring Schemes

When we refer to a jack or a patch panel's wiring connection, we refer to either the 568A or 568B wiring scheme, which define the pin-pair assignments for terminating UTP cable.

So, when someone refers to 568B, are they talking about the standard or the wiring scheme? It depends on the context. If someone were to say, "The entire office fully complies with 568B," they would be talking about the standard. If someone were to say, "The jacks and patch panels are all 568B, they would likely be referring to the wiring scheme. In UTP cable, each pair is represented by a specific color. Pair 1 is Blue, Pair 2 is Orange, Pair 3 is Green, and Pair 4 is Brown. In each pair, one wire is a solid color, and the other is predominantly white with a color stripe. When terminating UTP, each pair corresponds to a specific pin on the IDC contacts of the jack or patch panel, depending on which wiring scheme is used. The only difference between 568A and 568B is that Pairs 2 and 3 (orange and green) are swapped. The following charts illustrate the difference between the A and B methods. For those not familiar with telephony, tip (T) refers to the positive (+) side, and ring (R) refers to the negative side of the circuit.

568A Wiring
Pair # Wire Pin #
1 - White / Blue White / Blue 5
Blue / White 4