First, the physical structure of the interface is different
The RS232 interface comes in the form of 9 pins (DB-9) or 25 pins (DB-25), and there are two sets of RS232 interfaces on general personal computers, called COM1 and COM2.
The RS485 interface does not have a specific physical shape and is used according to the actual situation of the project.
Second, the interface electronic characteristics are different
The signal level of RS232 interface is high, which is easy to damage the chip of the interface circuit. The voltage of any signal line on the RS232 interface is negative logic. That is, logic \"1\" is -3 to -15V, logic \"0\" is 3 to 15V, and the noise tolerance is 2V. That is, the receiver is required to recognize a signal higher than 3V as a logical \"0\