0-9 key, send (0x30-0x39);
Clear, send (0x08)
F1, send (0x41)
F2, send (0x42)
Confirm, send (0x0d)
Decimal point, send (0x2e)

2,Communication command
Communication protocol: RS232, 19200, N, 8, 1.

* Clear screen command
    Format: ESC C 0
    HEX: 1B 43 30

* Display string command
    Format: ESC S 0 BYTE[0..6] CR
       HEX: 1B 53 30 BYTE[0..6] 0D
       Note: The character set displayed by the LED is limited to ‘0’-’9’ and the space keyboard.
   If the decimal point is to be displayed, the character +0X80H is transmitted.
      For example, to display 123.67, the number is:
        HEX: 1B 53 30 20 20 31 32 B3 36 37 0D

6-core M18 aircraft female
4—ground wire
1—Power supply (5V)
2—TX (send of terminal, receive by keyboard)
3—RX (reception of the terminal, connection of the keyboard)

The line is 3 meters long.