SG72 module is a communication port conversion module of USB<->RS232, USB <-> RS485, USB<->LINK (Smartgen special). 1, RXD LED: When ... , this light will flash.3, POWER LED: When the SG72 module successfully connect to USB, this light will be illuminated.4 ... , RS485: This is a generic isolation RS485 communication interface.7, RS232-C: This is a generic DB9 serial communication interface. sg72 module