The 568A and 568B standards were created to enable more effective communications for network cable segments over greater distances than nonstandard approaches. Because it utilizes light to carry data rather than electrical current, fiber optic cable is the only medium that is entirely resistant to crosstalk and EMI.
ANSI/TIA-568 is a technical standard for commercial building cabling for telecommunications products and services. The title of the standard is Commercial Building Telecommunications Cabling Standard and is published by the Telecommunications Industry Association (TIA), a body accredited by the American National Standards Institute (ANSI).
These standards specify a maximum segment length of 100 meters (328 feet) between connected devices. This length covers patch panels, modular jacks, and horizontal Ethernet cables. When extended lengths are required, switches, repeaters, or fiber optic media may be needed.
Under TIA/EIA-568-B, the maximum acceptable horizontal cable distance is 90 meters (295 feet) of installed twisted-pair cabling, with 100 meters (328 feet) of maximum total length including patch cords, and no single patch cord should be longer than 5 meters (16 feet).
What Are the Differences Between T568A vs T568B?
Network Ethernet cables are typically constructed of eight wires twisted together in four pairs, each of which consists of a solid colored wire and a stripe of the same color. Each pair is identified by one of four main colors and is designed to transmit a signal and its return.
A cable can be connected correctly in terms of continuity but not necessarily in terms of pairing. This is common when the cable is terminated similarly at both ends but in the incorrect sequence. To detect this sort of problem, a dynamic or AC test is necessary. If the only issue is a split pair error, the cable will continue to function normally but will most likely create crosstalk.
T568A and T568B both allow wiring schemes to connect network cables to eight-position RJ45 modular plugs, keystones, and patch panels. The only difference between T568A and T568B is that the orange and green pairs are switched, both are permitted under the ANSI/TIA-568 wiring standards.
Choosing between 568A and 586B Wiring
T568A wiring pattern is regarded as the preferred wiring pattern standard because it provides backward compatibility for both one pair and two pair USOC wiring schemes.
The U.S. Government requires the use of the preferred T568A standard for wiring done under federal contracts.
The T568B standard is the same as the older AT&T 258A color code and possibly the most widely used wiring scheme. It is also acceptable by the ANSI/TIA-568 standard, but it offers only a single pair backward compatibility to the USOC wiring scheme.
Only two pairs of wires (orange and green) are used in a 10/100BASE-T Ethernet network. The two additional colored cable pairs (brown and blue) are intended for additional Ethernet network applications or phone connections. Straight-through or cross-over cable may be required depending on the connection requirements.
What is USOC wiring?
The Universal Service Ordering Code (USOC) is a specification system developed by Bell Systems to connect equipment used in customer premises, such as homes and offices, into the greater public network.
The USOC is mainly a naming resolution for registered jack (RJ) wiring configurations used in telephone jacks or connectors that are still in active use today. A simple example is an RJ-11 jack, which comes in many variations, used to link telephones into the network interface.
What is Crosstalk? 
Crosstalk is the electrical induction of signals transmitted by one pair of wires onto another pair. The conductors do not need to make physical contact with each other as the crosstalk is transferred magnetically. This undesirable occurrence might cause data signal transfer to be slowed or entirely terminated over a long cable section. The wire twists featured in twisted pair Ethernet cable serve to greatly decrease crosstalk and its negative impacts.
What is EMI? 
Electro-Magnetic Interference (EMI) is an undesirable signal that is induced into a cable. The difference is that EMI is generally produced by a source outside of the cable. It can be a power cable or device, or in certain circumstances, neighboring Ethernet cables that do not comply with ANSI/TIA-568 specifications.
What is Attenuation? 
Attenuation is the loss of signal in a cable segment caused by wire resistance and other electrical variables that generate extra resistance. Longer cable lengths, poor connections, inadequate insulation, high levels of crosstalk, and EMI all contribute to an increase in overall attenuation.
What is a Straight Through Cable?
A Straight-through cable is a type of Ethernet cable in which the RJ-45 connectors at each end have the same pinout or color code used on both ends. A Straight-through cable is often referred to as a patch cable or patch cord. Straight-through cable is widely used to connect computers and other end-user devices to networking devices such as hubs & switches.
What is a Cross-over Cable?
A crossover cable can be used when connecting two devices of the same type, such as PC to PC, hub to hub, switch to switch connections. The crossover cable will execute the crossover operation physically. A crossover cable may be assembled using the 568A wiring scheme at one side and the 568B scheme at the opposite end. Pin 1 is crossed with Pin 3 and Pin 2 is crossed with Pin 6.
Syston Cable offers Premium Industry Standard Network Ethernet Cables in Cat 5E, Cat 6+, Cat 6A+, Cat 7A, and Cat 8 in Unshielded, Shielded, Riser-rated, & Plenum-rated.
Visit our webpage for all Syston Cable’s Network Ethernet Cables we have to offer: Network EtherNet/IP Cable
Written by Syston Cable Team
References:
www.techopedia.com
www.flukenetworks.com