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