RJ45 with transformers, also known as filters and isolation transformers, are widely used in RJ45 connectors. These products are used in RJ45 Ethernet, network routers, Ethernet switches, VDSL digital equipment, network set-top boxes, ADSL, EPON / GPON triple play equipment, EOC terminals, smart TVs, PC boards and other industrial equipment are rarely seen.

　　 For example, in an Ethernet device, when an RJ45 connector is used to connect through a PHY, a network transformer is added in the middle, and some transformers are connected to the power supply in the center of the transformer, and some transformers are connected to the ground. When connected to a power supply, the power supply value is generally divided into: 3.3V, 2.5V and 1.8V.

　　 There are five common types of network belt transformers for RJ45 connectors, which are divided into single port, dual port, multi port, 10/100BASE and 1000BASE-TX. Generally, those RJ45 connectors without network transformers have a very limited transmission distance under normal working conditions, and will also have some impact when connected to different levels of network ports. In addition, the external interference received by the chip is also very large.