RS232 to RS485 level conversion module:
Serial level conversion board, operating voltage 3.0V ~ 5.0V. The original chip MAX3232 / SP3232 / SP485 / MAX485, support Tx / Rx transceiver light, send and receive data when the respective flashing
TTL interface：
Pin 1 ---> V (3.3 - 5.0V)
Pin 2 <--- G（GND）
Pin 3 ---> B（Data -)
Pin 4 ---> A（Data +)
