Clarifying T568A/B Wiring vs EIA/TIA 568 Standard

#SuttleSaysPeople often confuse the TIA/EIA-568-B wiring standard with the T568A or T568B pin/pair assignment defined in this standard. According to this excerpt taken from, “TIA/EIA-568-B specifies that horizontal cables should be terminated using the T568A pin/pair assignments, or, optionally, per [T568B] if necessary to accommodate certain 8-pin cabling systems.” Despite this instruction, many organizations continue to implement T568B for various reasons, chiefly associated with tradition (T568B is equivalent to AT&T 258A). The United States National Communication Systems Federal Telecommunications Recommendations do not recognize T568B.”

T568A standard uses orange for line 2 and green for line 3, where T568B uses green for line 2 and orange line 3. Both are equal in performance, but care should be taken not to mix these wiring codes in the same installation (i.e., jack and patch panel must be wired the same). The same product can be used for either, as long as the pair order corresponds correctly. Most residential products are color-coded for T568A wiring as the default wiring standard.