Introduction - If you have any usage issues, please Google them yourself
hat is RS232/RS484 and its application?
QUOTE:
RS232 interface is the serial port, the 9 core (or 25 core) socket behind the computer chassis, next to the general "|O|O|" like logo.
The general chassis has two, and the new chassis may have only one. The laptop is probably not.
There are many industrial instruments that use it as a standard communication port. The content and format of the communication is generally attached to the user's Manual of the instrument.