hardwareNXPNXP_i.MX_8MMiniRSB-3730 Yocto4.2 Release NotesRSB-3730 Connector COMRSB-3730 Connector COM RS232&R485 (COM) RSB-3730 have one RS232 &RS485 DB9 com port, you can select RS232 or RS485 by setenv on uboot.