What is T568A wiring?

The T568A standard provides a uniform method for terminating Ethernet cables. In every Ethernet cable, there are multiple individual wires. The term "termination" refers to connecting these wires to some hardware, such as an RJ45 plug or a patch panel jack.

What is T568A wiring?

T568A is a cabling standard developed by the Telecommunications Industry Association (TIA) and the Electronic Industries Alliance (EIA). This standard defines the order of the four twisted pairs in Ethernet cables.

T568A Explanation

Internally, an Ethernet cable consists of four twisted pairs of wires. In a T568A cable, these wires are arranged in a specific order before being terminated into an RJ45 jack or port. This allows two network devices connected using an Ethernet cable to communicate because the wires in one port will match up with the same wires in the other port.

Is TIA/EIA-568A the same as T568A?

TIA/EIA-568A is the same as T568A. T568A is just an abbreviated version of TIA/EIA-568A.

What is the most common use of T568A?

The T568A is commonly used in any Ethernet cable used to connect two network devices (such as a computer's network card) to a switch or network patch panel.

T568A wiring working principle

Ethernet cabling seems simple enough, but there are some specific things you should know that affect the importance of standards like T568A. Inside the cable, there are eight individual wires and a plastic insert. Each wire terminates in a pin in the connector, and the order is very important.

T568A Color Code

The four pairs of wires in Ethernet cabling always have four colors: green, blue, orange, and brown. One of each pair is a solid color; the other is a stripe of color and white. The colors are used to describe the order of the wires when they are terminated.

T568A cable structure

In addition to the four twisted pairs, cables using T568A contain a plastic insert, sometimes called a star filler. It helps reduce interference and adds density to support the cable and minimize bends. A jacket covers the wires and plugs to protect them.

T568A Pinout

The RJ45 connector has eight pins, one for each wire. Each wire is terminated to one of the eight pins. The order of the wires determines whether the cable complies with the T568A standard.

T568A wiring configuration

The T568A wiring standard states that the wires are arranged in the following order, starting with the first pin on the RJ45 jack: Green/White, Green, Orange/White, Blue, Blue/White, Orange, Brown/White, Brown. This can be more easily seen in the image below.

T568A wiring diagram and example

This diagram shows the wiring sequence for the T568A, as if looking at an RJ45 connector.

568A wiring diagram

T568A and T568B

However, T568A is not the only wiring standard in existence, there is also the very similar T568B.

What is T568B?

The T568B standard is very similar to T568A, except two pairs are swapped: green and orange. The wiring order for T568B is: orange/white, orange, green/white, blue, blue/white, green, brown/white, brown.

Are TIA/EIA568A and TIA/EIA568B interchangeable?

No, these standards are not interchangeable. For example, if you are installing wiring and wire a patch panel with one standard and a network jack with another standard, the devices connected via that wire will not be able to communicate, effectively being connected to different pins at each end.

Either standard can be used as long as all wiring in the network remains consistent, but T568A is more common.

What is a Crossover Cable?

A cable that follows either standard on both ends of the cable is called a "straight-through" cable, as all the wires run straight through the same pins on both connectors. This is called a "crossover," where one end of the wire uses T568A and the other uses T568B.

Crossover cables can be used to connect two ports that use different wiring standards. However, they are more commonly used to connect two devices of the same type together, such as connecting two computers directly to each other's network cards.

How do crossover cables relate to T568A?

One end of the crossover cable is wired according to the T568A standard, and the other end is wired according to the T568B standard.

Summarize

The T568A wiring standard is essential for cable terminations throughout the network. It ensures consistency and conformance between devices, ensuring reliable communication between devices. By adhering to this standard, network managers can ensure that their devices can communicate with reliability at optimal performance.