RS485 is an electrical signal standard that supports long-distance, multi-point communication and is suitable for scenarios such as industrial automation;
RJ45 is a physical connector (8P8C structure) used for Ethernet protocols to achieve short-distance, high-speed data transmission.
The essential difference between the two is that RS485 defines differential voltage signals (±2V to ±6V), while RJ45 is a physical interface carrier that carries network protocols.
Modbus RTU: An industrial communication protocol built on the RS485 physical layer. It uses a master-slave communication mode, with the host initiating data exchange and the slave responding passively. It supports register reading and writing, error detection, and other functions. It is widely used in scenarios such as PLC control and smart instruments.
Modbus TCP: Based on Ethernet and TCP/IP protocols, it uses standard network equipment (such as switches and routers) to connect, supports long-distance communication and high-speed data transmission, but requires high network stability.
