Test of the RevPi Connect 4 RS485 interface with python serial.

serial_test.py

#!/usr/bin/env python3

from serial import Serial
from serial.rs485 import RS485Settings

# Configure the serial port with RS485 settings (with RTS level set for tx and rx)
s = Serial(port='/dev/ttyRS485', baudrate=9600, bytesize=8, parity='N', stopbits=1)
s.rs485_mode = RS485Settings(rts_level_for_tx=False, rts_level_for_rx=True)

try:
    while True:
        c = s.read(1)
        if c:
            print(c)
            msg = b'rx: ' + c.upper() + b'\r\n'
            s.write(msg)
except KeyboardInterrupt:
    pass