UART

TTL

Full Duplex

device name: "/dev/ttyTHS1"

RS232

Full Duplex

device name: "/dev/ttyTHS3"

RS485

Half Duplex

device name: "/dev/ttyTHS4"

before send: "echo 1 > /sys/class/leds/rs485_re_de/brightness"

before receive: "echo 0 > /sys/class/leds/rs485_re_de/brightness"