年表作成・共有サービス - pastport

Mini PC is a small-sized computer that can perform various tasks such as web browsing, media streaming, gaming, and office work. Mini PC usually has limited space and power consumption, which makes it suitable for embedded systems and IoT applications. However, mini PC also needs to communicate with other devices, such as sensors, controllers, printers, and monitors. How can mini PC achieve reliable and efficient serial communication with these devices? This article will introduce two common serial protocols: RS485 and RS232, and compare their applications and differences in mini PC.

1. What is RS485?

RS485, or EIA-485, is a serial protocol that uses balanced differential signaling to transmit data over long distances and noisy environments. RS485 can connect up to 32 devices on a single bus, using two or four wires. RS485 can operate in half-duplex or full-duplex mode, depending on the number of wires. In half-duplex mode, only one device can transmit data at a time, while the others listen. In full-duplex mode, two devices can transmit and receive data simultaneously, using separate pairs of wires.

RS485 has several advantages over RS232, such as:

• Higher noise immunity and signal quality, due to the use of differential signaling and twisted-pair wires.

• Longer transmission distance, up to 1.2 km, compared to 15 m for RS232.

• Higher data rate, up to 10 Mbps, compared to 1 Mbps for RS232.

• Lower power consumption, due to the use of low-voltage levels, from -7 V to +12 V, compared to +/- 25 V for RS232.

• More devices on a single bus, up to 32, compared to 2 for RS232.

1. What is RS232?

RS232, or TIA/EIA-232, is a serial protocol that uses unbalanced voltage level signaling to transmit data over short distances and low noise environments. RS232 can connect only two devices, using 9 or 25 wires. RS232 operates in full-duplex mode, meaning that both devices can transmit and receive data simultaneously, using different wires.

RS232 has some advantages over RS485, such as:

• Simpler wiring and connection, due to the use of fewer wires and connectors.

• Simpler protocol and implementation, due to the use of point-to-point communication and direct voltage levels.

• Wider compatibility and availability, due to the long history and popularity of RS232.

1. Applications and Differences in Mini PC

Both RS485 and RS232 can be used for serial communication in mini PC, depending on the requirements and scenarios. Some examples of applications and differences are:

• RS485 is more suitable for industrial and outdoor applications, where the mini PC needs to communicate with multiple devices over long distances and noisy environments, such as sensors, controllers, and actuators. RS485 can provide reliable and robust data transmission, with minimal interference and signal degradation.

• RS232 is more suitable for personal and indoor applications, where the mini PC needs to communicate with one device over short distances and low noise environments, such as printers, monitors, and keyboards. RS232 can provide simple and easy data transmission, with minimal wiring and configuration.

• RS485 requires a converter or an adapter to connect to the mini PC, since most mini PC do not have a native RS485 port. RS232 can be directly connected to the mini PC, since most mini PC have a native RS232 port or a USB port that can be converted to RS232.

• RS485 requires a termination resistor at each end of the bus, to prevent signal reflection and distortion. RS232 does not require any termination resistor, since it uses point-to-point communication.

• RS485 requires a master-slave or a peer-to-peer protocol, to coordinate the data transmission and avoid data collision on the bus. RS232 does not require any protocol, since it uses direct voltage levels.

1. Conclusion

RS485 and RS232 are two common serial protocols that can be used for serial communication in mini PC. They have different characteristics and advantages, depending on the applications and scenarios. RS485 is more suitable for long-distance and multi-point communication, while RS232 is more suitable for short-distance and point-to-point communication. RS485 requires more wiring and configuration, while RS232 requires less wiring and configuration. RS485 and RS232 can be converted and connected to the mini PC, using converters, adapters, and USB ports. By choosing the appropriate serial protocol, mini PC can achieve reliable and efficient serial communication with other devices.
https://www.inctel.com.cn/product/fanless-industrial-mini-pc-j4125/