What Is a RJ45 Socket?

RJ45 is a type of information socket (ie communication lead-out) connector in the wiring system. The connector consists of a plug (connector, crystal head) and socket (module). The plug has 8 grooves and 8 contacts. RJ is the abbreviation of Registered Jack, which means "registered socket". In the FCC (Federal Communications Commission Standards and Regulations), RJ is an interface describing public telecommunication networks, and RJ45 of computer networks is a popular name for standard 8-bit modular interfaces.

The information module or RJ45 connection plug and the twisted pair are terminated in two structures, T568A or T568B. In T568A, the eight wires connected to it are defined as: white green, green; white orange, blue; white blue, orange; white brown, brown. In T568B, the eight wires connected to it are defined as: white orange, orange; white green, blue; white blue, green; white brown, brown. The defined differential transmission lines are white-orange and orange cables, white-green and green cables, white-blue and blue cables, and white-brown and brown cables.

In order to achieve the best compatibility, the T568B standard is generally used when making straight lines. The serial number of the RJ45 crystal head pin should be observed as follows: Turn the front of the RJ45 plug (the side with the copper pin) toward itself, the side with the copper pin upward, and the end of the connecting cable facing downward. The needles are numbered sequentially from 1 to 8.

Distinguish between RJ45 and RJ11 interfaces ^[11]

There will also be an RJ11 interface on the home ADSL Modem (modem), which is slightly smaller than the RJ45 interface and is mainly used to connect telephone lines. It should be noted that the RJ11 interface is 4 or 6 pins, and the RJ45 is an 8 pin interface, so the RJ45 plug cannot be inserted into the RJ11 interface, otherwise the RJ11 plug cannot be inserted into the RJ45 interface (although it can be realized on the physical interface) In actual use, it must be clearly distinguished ^[11] . RJ45 fixed links are backward compatible with RJ11. RJ45's 3-6 and 4-5 line pairs correspond to RJ11's 1-4 and 2-3 line pairs.