Different fieldbus devices have a variety of integrated communication bus connection interfaces. Below, we will list a few common ones, I don't know if you have encountered them all.
1. Terminal interface, according to its design, can be divided into 3P terminal, 4P terminal, 5P terminal, etc., etc., which is the most widely used type of bus wiring method. Think about it, no matter what bus, it is a "wire", the terminal can be connected to any wire, naturally the most widely used.
2, DP9 interface, it appears on some bus analyzers or bus gateways, its interface has 9 wiring pins. In actual use, we may only use a few of these nine pins, and the other pins are not connected.
3. OBD interface is generally used on bus equipment related to automotive buses, because the bus interface of automobiles is OBD type.
4. RJ45 network port, which is the interface type of the crystal head we usually install the network cable, which can connect 8 lines. As with the DB9 connector, we may only use a few of the 8 wires, and the others are not. Therefore, do not encounter the RJ45 port to say that this is an Ethernet port, or it may be an RS232 port.
5, USB interface, this does not need to be introduced, there are a variety of USB devices around us, common USB cables are USB min, USB micro, USB lighting, USB type-C and so on.
Now are you clear? Feel free to find me to continue to understand.