SG72 module is a communication port conversion module of USB<->RS232, USB <-> RS485, USB<->LINK (Smartgen special). 1, RXD LED: When PC(personal computer) receives data, this light will flash.2, TXD LED: When PC sends out data, this light will flash.3, POWER LED: When the SG72 module successfully connect to USB, this light will be illuminated.4, USB interface: Connect SG72 module to the USB ...