COM products commonly used in industrial computers generally have two interfaces: RS-232 and RS-485. From the appearance, both serial ports use 9 pins.
COM port is a kind of communication port, which can be used for a variety of communication equipment.
Hospital medical equipment control: hospital gastroscope, CT, chest X-ray instrument, etc.
Supermarket charging related equipment: small ticket printer, card reader, bar code grabber, etc.
Engineering production design control: PLC programmer.
Computer extended peripheral equipment: such as printer, serial mouse, serial keyboard, etc.
Extended data:
The difference between serial port, COM port, TTL, RS-232 and RS-485;
1, serial port and COM port refer to physical interface forms (hardware). TTL, RS-232 and RS-485 refer to level standards (electrical signals). ?
2. When connecting devices, generally only GND RX TX is connected. Vcc or +3.3v power cord will not be connected to avoid power conflict with the target device. ?
3.PL2303 and CP2 102 chips are USB-to-TTL serial chips, which use USB to expand the serial port (TTL level).
4.MAX232 chip is a special bidirectional conversion chip for TTL level and RS232 level, which can convert TTL to RS-232 or RS-232 to TTL. ?
5.TTL standard is that the low level is 0 and the high level is 1(+5V level). The RS-232 standard is that the positive level is 0 and the negative level is 1 (15V level). ?
6.RS-485 is similar to RS-232, but adopts differential signal negative logic.
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