The computer is generally 232 interface, according to the definition of the serial port of the computer, it should also be 232 interface, 232 and 485 interface appearance to distinguish the specific operation method is as follows: first, through different characteristics to distinguish: 1, 485 interface: logic \"1\" to the voltage difference between the two lines is (2-6) V; The logical \"0\" is represented by the voltage difference between the two lines as - (2-6) V.
2, 232 interface: Because the external power supply mode is not used, you must take power from the RS-232 interface line to supply power to internal components. 1, 485 interface: the interface signal level is lower than RS-232-C, it is not easy to damage the chip of the interface circuit, and the level is compatible with the TTL level, which can be easily connected with the TTL circuit.
2, 232 interface: RS-232 communication interface adopts level mode transmission, suitable for point-to-point communication, without special transceiver enable control. 1, 485 interface: The combination of balanced driver and differential receiver, anti-common-mode interference ability is enhanced, that is, anti-noise interference is good.
2, 232 interface: The converter power supply from the RS-232 signal line, its input power is limited, so in this design will be as far as possible to use 3V power supply of low-power devices.
Usually the computer serial port is RS232, if there is, of course, the industrial control will have RS485 interface
Of course, the serial port of the general computer is RS232. However, some industrial computers can choose RS485 interface. RS232 is one of the communication interfaces on personal computers, developed by the Electronic Industries Association (EIA) asynchronous transmission standard interface.
Usually the RS-232 interface comes in the form of 9 pins (DB-9) or 25 pins (DB-25), and there are two groups of RS-232 interfaces on general personal computers, called COM1 and COM2. RS232 is different from RS485 pins, RS232 standard is 9 pins, and RS485 is generally A, B and a total of 3 pins. The standard configuration window on the computer is RS232 window, if you want to become RS485, you need to use a special RS232 to RS485 hardware conversion interface for conversion. Although the RS232 interface is slow, it is widely used because of its standardized design (the asynchronous transmission standard interface developed by the Electronic Industries Association (EIA)), which can be used on many devices.