| There are two wiring standards for network | | | | If none of the factors above apply, either T568A |
| cabling. T568A and T568B are the two standards | | | | or T568B may be used. It is important to ensure |
| for the RJ-45 or 8-position modular connector, | | | | that the workstation connectors and the patch |
| permitted under the TIA/EIA-568-A wiring | | | | panels are wired to the same pattern. T568B is |
| standards document. The only difference between | | | | commonly used in commercial installations, while |
| T568A and T568B (also known as Weco, | | | | T568A is prevalent in residential installations. For |
| AT&T 258A) is that the orange and green | | | | these reasons, we almost always use T568B for |
| wire pairs (pairs two and three) are interchanged. | | | | unspecified installations. |
| How to decide which wiring pattern to use: | | | | One bonus is that most networking equipment |
| 1. Does the job specification call out a wiring | | | | presently on the market have wiring diagrams for |
| pattern? | | | | either T568A or T568B. Since the difference is |
| 2. Does the customer/end user have a | | | | only the switching of two pairs of wires, it is easy |
| preference for T568A or T568B? | | | | enough for manufacturers to print both standards |
| 3. Have patch panels already been purchased for | | | | on their hardware. For example, a patch panel |
| the job? If so, they will probably be either T568A | | | | that is labeled for T568A/T568B will usually have |
| or T568B. The jacks should be wired to the same | | | | the color-coded wiring diagrams above and below |
| pattern as the panels. | | | | the actual punchdown. One will typically be labeled |
| 4. Are you adding on to an existing wiring plant? If | | | | T568A and the other T568B. This type of |
| so, your new wiring should match the existing | | | | hardware is preferred by installers due to its |
| wiring. | | | | flexibility. |