10/100 Base TX RJ45 interface is commonly used in Ethernet interface, support for network connection speed of 10Base and 100Base of adaptive common RJ45 connector into two categories: for Ethernet cards, routers and Ethernet interface DTE type, for switches DCE type. DTE can be called data terminal equipment; the DCE can be called data communications equipment. In one sense, the DTE device is called the "active communications equipment DCE device called a" passive communications equipment. When the two types of devices use RJ45 interface communication, you must use a crossover cable. This can be defined from the following types of pin definitions of the RJ45 the DTE and RJ45 DCE type pin. The RJ45 network cable connector also known as crystal head which a total of eight cores made ??of, widely used in LAN and ADSL broadband Internet connection to the users cable network equipment which named as CAT cables or twisted-pair. In the specific application, the RJ45-type plugs and cables, there are two connection methods, respectively called T568A line sequence and T568B linear order.