The RJ-45 is the most common physical interface used to terminate data cables. Includes a male (connector) and female (jack) version and it is usually made in ABS, including pins covered in gold (with different microns of cover) for its connectivity. They include eigth pins or electrical connections. The acronym "RJ" stands for "Registered Jack" and the "45" specifies how the pins are numbered. They are both defined by the standard TIA/EIA-568-B, which defines the position of the pins.