Communication interface design refers to the interface between the central processing unit and the standard communication subsystem. Such as RS232, RS422, RS485 and other communication interfaces. Many transmitters use RS485 as a standard communication port. The content and format of the communication is usually attached to the transmitter’s instruction manual. RS232 is a communication standard originally used for modems, printers, and other PC peripherals, while RS-232 is only used in point-to-point communication systems, not multipoint communication systems, and all RS-232 systems must comply with these limitations. RS422 is a one-way, full-duplex communication protocol suitable for noisy industrial environments. The RS-422 specification allows a single driver to communicate with multiple receivers, and the data signal is transmitted differentially at rates up to 50Mbps. RS485 is a bidirectional, half-duplex communication protocol that allows multiple drivers and receivers to be hooked up to a bus, each of which is able to be off-bus. This specification meets all RS422 requirements. And it is more stable than RS422. It has a higher receiver input impedance and a wider common-mode range. What limits the data rate of the transmitter RS485? 1. Cable architecture: Category 5 24AWG twisted pair is the most commonly used cable in RS-485 system, and the shielded cable can greatly enhance the noise suppression ability and improve the data transmission rate at a certain distance. 2. Cable characteristic impedance: Distributed capacitance and distributed inductance will reduce the edge speed of the signal, thereby reducing the noise margin and compensating for the “eye template” characteristics. The distributed resistance directly leads to the attenuation of the signal level. 3. Driver output impedance: too high impedance will limit the driving ability. 4. Terminal matching: long cables can be regarded as transmission lines. A terminating resistor with a connection resistance on the cable that is equal to the characteristic impedance of the cable reduces signal reflection and increases the data rate. 5. Noise margin: the larger the value, the stronger the line’s tolerance to interference, reflecting the more stable the connection rate and the less susceptible to interference. If you have any questions about product consultation, product customization, agency, technical inquiry, quotation, etc., please contact Xingyi, 400-600-4496!