BROCADE IP PRIMER

Layer 1 Ethernet (Cabling)Twisted Pair is actually a bundle of eight smaller cables-four pairs. Each pair istwisted around each other many times throughout the length of the cable. Thecables are twisted to help block crosstalk. This would be when the electricalsignal on one of the other pairs crosses over to any of its neighboring pairs. Italso helps to minimize electromagnetic interference (EMI). Any time an electricalcircuit is rapidly changing signals, EMI becomes the by-product. It's a signalfield emitted by the circuit, and it can interrupt other nearby legitimate circuits,if you're not careful. STP is still used for this purpose. This adds additionalinsulation and EMI shielding.The cable comes to an end called RJ45. As you can see from the diagram, ithas eight metal positions called pins. Each pin connects with one of the eightwires inside the cable.You may, or may not, have noticed that the eight cables inside are aligned in acertain order. This conforms to one of two standards put forth by the TelecommunicationsIndustry Association/Electronic Industries Association (TIA/EIA).The standard is called TIA/EIA-568-B.1-2001. It specifies that there are twomethods for aligning the cables. They are labeled T568A and T568B. Casually,these are referred to as the A-standard and B-Standard.To see which standard a particular cable uses, hold the RJ45 end in front ofyour face with the clip-side away from you. Then, read the colors from left toright.T568A1 White with Green stripe2 Green3 White with Orange stripe4 Blue5 White with Blue stripe6 Orange7 White with Brown stripe8 BrownT568B1 White with Orange stripe2 Orange3 White with Green stripe4 Blue5 White with Blue stripe6 Green7 White with Brown stripe8 BrownBrocade IP Primer 23