RS-485, which stands for "Recommended Standard 485," is a serial communication standard used to transfer data between electronic devices. It is a variant of the RS-232 standard, which is commonly used in industrial automation, instrumentation, building automation, remote monitoring and other fields, especially for data transmission requiring long distance and high noise environments.

Here are some of the key features and benefits of RS-485:

Differential signal: RS-485 transmits data using a differential signal, which means it transmits both positive and negative signals, thus reducing the impact of electromagnetic interference. This allows the RS-485 to perform well in noisy industrial environments.

Multi-point communication: RS-485 supports multi-point communication, which means that multiple devices can be connected to the same bus to communicate. Each device has a unique address, and only the device being addressed receives and responds to the data.

Long-distance transmission: RS-485 can support long communication distances, often up to thousands of feet (hundreds of meters), which makes it suitable for data transmission in large plants and facilities.

High data rates: RS-485 supports high data transfer rates, typically ranging from a few hundred bits per second (bps) to several megabits per second (Mbps), depending on the specific implementation and device.

Half-duplex or full-duplex: The RS-485 can operate in half-duplex or full-duplex mode. In half duplex mode, devices can alternately send and receive data, while in full duplex mode, they can send and receive data simultaneously.

Wide range of applications: RS-485 is used in a wide variety of applications, including data acquisition, monitoring systems, industrial controls, security systems, building automation and instrumentation.

It is important to note that RS-485 usually requires additional hardware support, such as drivers and receivers, to ensure proper data transmission. In addition, the protocols and data formats for communication often need to be configured and managed according to the specific application and device.