Aimed at the novice installer, a video lecture produced by CableSupply.com nicely sums up the functions of the pins and wiring in Ethernet cables and RJ45 plugs. The presentation succinctly explains the TIA/EIA-568A and 568B color codes, what they mean, and why they're important. Also discussed: when and why to use a straight-through cable versus a crossover cable.
See also:Ethernet cable bundling, patch panel termination techniques demonstrated