Amazon: usb to db9 pinout wwwon›Search›usb to db9 pinoutFTDI USB RS232 Cable to DB9 Male Full Pinout Compatible with UC232 US232 Micro USB Serial Cable Type C Serial Cable (150cm Micro USB ft232r) by Usangreen. $15 $ 15 00 Prime. FREE Shipping on eligible orders. Only 10 left in stock - order soon. RS232 serial to USB converter cable schematic · AllPinouts RS232 serial to USB converter cable schematic. interface converter cable for interconnection of USB and RS232 serial interfaces 4 pin USB A / USB B / mini-USB jack connector at the computer’s USB cable 9 pin D-SUB female connector at the computer’s serial cable.