The basic knowledge of RS232 communication: RS232 communication is also called serial communication mode. It refers to the way that the computer uses the serial port cable and the single device (controller) to communicate through the RS232 international standard protocol.
Communication distance: 9600 baud is recommended within 13 meters.
Communication rate (baud rate): The default is 9600 bps, and the common ones are 1200 2400 4800 19200 38400. The larger the baud rate, the faster the transmission speed, but the shorter the stable transmission distance, the worse the anti-interference ability.
In the marine survey field work, the most used serial port RS232, but it has a lot of shortcomings, that is, the transmission distance is short, no more than 15m, if long distance transmission, you need to think of another way. For example, on the ship, from the cab to the laboratory, after several layers, it can be transmitted by network cable. The transmission distance of Category 5-6 cable is 80-100m, so RS232 to RJ45 is needed.
Sequence and definition of RJ45 line
1 --- orange white, 2 --- orange, 3 --- green white, 4 --- blue, 5 --- blue and white, 6 --- green, 7 --- brown, 8 --- Brown.
If the line is connected, it can be used as a network cable. If the RS232 line 2, 3, and 5 are directly used, the transmission distance of the network cable is only used. I try it, and there is no problem at all.