Connecting RS-485 to TTL converter for Arduino -- RS-485 on the max485 and USB to rs485 converter. Contact RE and DE impoverish when filing they signal they will translate converter from a read mode to the transmission mode. R0 connect to RX0 Arduino. DI connect the Arduino to the TX1. The USB to rs485 converter changes the mode automatically, in the usual pezhime he reads from the bus as soon as the signal is received from the com port switches to transfer mode.