It is the most common cable for network connections for example to the Internet.
This type of cable has 8 pins of electrical connections. Its connector is called 8P8C connector (8 positions and 8 electrical contacts).

This connector is physically compatible with the connector RJ11

RJ11

RJ11 - Registered Jack 11 - is used for the landline telephone. It is an international standard that is used to connect the landline telephone to the Telecommunications network. RJ11 uses a 6-slot connector. In it RJ11 has 6 slots (positions) and two conductors, the standard is written 6P2C.
The information transmitted on the line can be digital (DSL) or analog.

if an adapter is used.
On computer cabling RJ45 In 10/100 Mbit/s, only 4 pins 1-2 and 3-6 are used to transmit information.
In 1000 Mbps (1Gbps) of transmission, the 8 pins of the socket are used.
Two cabling standards RJ45 are mainly used to wire sockets : the standard T568A and the standard T568B.
These standards are very similar : only pairs 2 (orange, white-orange) and 3 (green, white-green) change.

The cabling industry uses cabling code standards. These standards allow technicians to reliably predict how the Ethernet cable terminates at both ends in order to facilitate the work of technicians, it serves as a benchmark and allows to know the function and connections of each pair of strands.
Ethernet cable socket cabling follows standards T568A and T568B.

There is no electrical difference between the different strands T568A and T568B, so neither is better than the other. The only difference between them is how often they are used in a particular region or type of organization.
Thus, your choice of color coding will largely depend on the country in which you work and the types of organizations for which you install it.

The right cable (marked PATCH CABLE or STRAIGHT-THROUGH CABLE ) is used to connect a device to a network hub or network switch. The strands are connected in a straight line to the 2 connectors, the same strand on the same contact.

The cross cable (marked CROSSOVER CABLE along its sheath) is in principle used to connect two hubs or network switches, between one of the normal ports (MDI) of greater capacity, and the upstream port MDI-X of lower capacity wishing to share the bandwidth of the upstream network equipment.

The only difference is the position of the green and orange pairs. But apart from this provision, there are two or three other compatibility factors that can also make a difference. To date, T568A has been largely replaced by the standard T568B. This corresponds to the old color code of the standard 258A d'AT&T (American company) and at the same time accommodates present and future needs. In addition T568B is also compatible with the U.S. Bureau of Standards (USOC), although only for a single pair. Finally T568B is generally used in commercial facilities, while T568A is rather prevalent in residential facilities.

It can be noted that in the case of short-length straight cables sold or distributed already set on the market, the two standards are compatible with each other, since the color permutation does not change the electro-magnetic properties of each of the twisted pairs.

The cross cable (marked CROSSOVER CABLE ) is typically used to connect two network hubs or switches.
Pairs 2 and 3 are crossed keeping the same polarity. Pairs 1 and 4 are also crossed, but in addition to this, the strands that make up each of these pairs are also crossed, causing a change in polarity.

T568B is the standard followed by the majority of Ethernet installations in the United States. This is the most commonly used standard for business cabling.

Called Ethernet cables. The so-called cables Cat5, Cat6 and Cat7 are the most commonly used RJ45 cables in current network connections.
There are 6 categories of cords RJ45 of transmission. For a private network a cable RJ45 category 5 is sufficient. For larger networks, there is a cable RJ45 higher category (5E or 6).

Category 5 was originally designed to transmit at frequencies of 100 MHz, offering a nominal line speed of 100 Mbit/s. Cat 5 uses two twisted pairs (four contacts) with a maximum range of 100 meters. A specification Cate5e was then introduced with stricter specifications and standards. The new standard also required new cables to include the four twisted pairs.

Over short distances, under ideal signal conditions and assuming they have four pairs, the connecting cables Cat5 et Cat5e are capable of transmitting at Gigabit Ethernet speeds.
Gigabit Ethernet uses an optimized encoding scheme specifically designed to operate within these lower signal tolerances.

Backwards compatible with Cat5e, Category 6 has strict standards and significantly improved armor. The cable Cat6 was designed as the standard for Gigabit Ethernet, offering native speeds of up to 1000 Mbps on a frequency of 250 MHz. By reducing the maximum cable distance from 100 meters to 55 meters, 10 Gigabit Ethernet is supported.

Cat6a doubles the frequency to 500 MHz while continuing to reduce sound interference with grounded sheet shielding. These enhancements remove the cable distance penalty when operating in 10 Gigabit Ethernet.

Operating at frequencies up to 600 MHz, Cat7 has been specifically designed to support 10 Gigabit Ethernet rated speeds. In addition to the shielding introduced by Cat6e, this new specification provides individual shielding for each of the four twisted pairs.
Cat7 has a maximum distance of 100 meters while maintaining backward compatibility with Cat5 and Cat6. Cat7a increases frequencies to 1000 MHz, providing an increased specification capable of supporting future 40/100 Gigabit Ethernet speeds. The increase to 1000 MHz also allows the transmission of low-frequency cable TV streams.