The serial port is a very common device communication protocol on a computer. Most computers contain two RS232-based serial ports. The serial port is also a common communication protocol for instrumentation equipment; many GPIB-compatible devices also have an RS232 port. Because rs232 is easy to use and easy to operate, directly use a usb to rs232 serial cable to connect the device to the computer and the transmission is stable. At the same time, there is a big disadvantage. The RS-232 bus uses a balanced transmission technology, which limits its transmission distance to about 15 meters. What if the distance between the equipment and the control room is more than 15 meters?
When the distance exceeds 15 meters, it is not suitable for USB to RS232 to connect and convert. The solutions can be as follows: Select products according to your own environment and distance to solve the problem of RS232 transmission distance.
1) RS232 to RS485 converter can be used to convert single-ended RS-232 signals into balanced differential RS-485 signal transmission, which can extend RS-485 communication distance to 1.2 km. It ensures that the program written in RS-232 mode can be run in RS-232 mode without modification, ensuring that it is suitable for existing operating software and interface hardware. The converter transmission rate is 300-115.2Kbps.
2)Use rs232 to Ethernet converter to provide RS232 to TCP/IP network and TCP/IP network to RS232 data transparent transmission, it can make the device with RS232 serial port immediately have the function of connecting to TCP/IP network, Distributed serial devices and hosts are centrally managed through the network. Another method can use rs232 to fiber converter, the transmission is very very stable, the transmission distance of single mode fiber can reach 20KM. These are all desirable methods, but the cost is relatively high. There is also an easier way to recommend a pair of RS-232 long-line drivers that can extend the distance directly to 1200 meters.
