This video lecture explains the pins and wiring in Ethernet cables and RJ45 plugs. We look at the 568A and 568B color codes, what they mean, and why they're important. We also discuss when and why to use a straight-through cable versus a crossover cable.
Color-coded wiring sequences exist as a cabling industry standard. It allows cabling technicians to reliably predict how Ethernet cable is terminated on both ends so they can follow other technicians' work without having to guess or spend time deciphering the function and connections of each wire pair. Ethernet cabling follows the T568A and T568B standards.
There is no electrical difference between the T568A and T568B wire sequences, so neither is inherently superior. The only difference between them is how frequently they are used in a particular region or type of organization. So, your choice of color code - which one is "right" - will largely depend on the country you work in and what types of organizations you install for.
T568B is the standard followed by the majority of Ethernet installations in the United States. It is the more common standard used when cabling for businesses, offices, commercial buildings, and non-profits.
T568A is the majority standard followed in European and Pacific countries. It is also used in all United States government installations.
Either standard is acceptable in most cases. You can use either one as long as you're consistent. When entering a new job, you may want to take a look at any pre-existing cabling to see which standard is already in use at that location.
Cablesupply.com carries bulk Ethernet patch cables in cat6, cat5, and cat5e which are a twisted pair cable consisting of four pairs that can be used in voice, data, and video applications. read more
Bulk Ethernet Cable
Data lines require all four pairs however four voice lines could be used on the same cable because voice only requires one pair. This could be useful if one were running four separate lines to a single location; just one cable could be punched down onto four separate RJ11 jacks. They commonly come in three colors: white, blue and black. The color does not affect the performance of the cable in any way but can be useful when running multiple lines. For example: all data lines could be run on blue cable and all voice lines could be run on only white cables to easily differentiate your groups of cables expediting the drop and termination of the cable. Our cat6 bulk Ethernet cable is backwards compatible with our bulk cat5e cable and even cat3; however, if a lower graded jack is used with cat6 cable it does reduce it to that grade of cable qualtiy; similarly if a cat6 jack were used to terminate a cat5e cable it would have no cat6 qualities. The main difference between cat6 and cat5e cable is that cat6 has reduced crosstalk or EMI (Electro-Magnetic-Interference) and where cat5 and cat5e have a 100 MHz performance, cat6 can perform up to 250MHz, and cat6e can perform all the way to 500MHz. Crosstalk is an undesired affect that occurs when other nearby cables, motors, the electrical fallout from a nuclear blast or other electronic devices interfere with the transmission on each cable therefore slowing down the flow of information or possibly cutting it off all together. Crosstalk can be greatly reduced in Cat5 and Cat6 cable by buying bulk Ethernet cable that is shielded. Shielded cable has an aluminum shield around the four twisted pairs; this shield absorbs any potential crosstalk or EMI but this electricity needs to be drained somewhere so the cable also has a drain wire that must be connected to a ground. Though there are many options for bulk Ethernet patch cables, learning which cable best suits your needs is important but being over prepared for your needs is not a bad decision as your cable will most likely outlive your devices which will require higher grade cable as time goes on.