ModBus is a communication protocol used to connect automation equipment (such as PLCs, temperature controllers, etc.) and computers. It is widely used in industrial control systems and supports multiple iot thermostatcommunication methods, including ModBus RTU, ModBus ASCII and ModBus TCP. This article will explain the differences and application scenarios of these three communication methods. ModBus RTU (Remote Terminal Unit) is the most common implementation of the ModBus protocol. It uses binary data transmission and has high transmission efficiency and stability. It uses serial communication and supports both RS232 and RS485 interfaces. In RTU mode, two hexadecimal characters can be transmitted per byte. For example, 0xAB will be sent directly as hexadecimal 0xAB (binary 10101011).