Hi Not sure my reply posted so here it is again. Change the mode from USB-D to U-DIGI in the INI file as below. [Xiegu X6100] CmdType=HEX PTTOn=FEFE70E01C0001FD PTTOff=FEFE70E01C0000FD ModeUSB=FEFE70E00601FD ModeU-DIG=FEFE70E00608FD ModeFM=FEFE70E00605FD

Just changed the USB-D to the following in the INI file. [Xiegu X6100] CmdType=HEX PTTOn=FEFE70E01C0001FD PTTOff=FEFE70E01C0000FD ModeUSB=FEFE70E00601FD ModeU-DIG=FEFE70E00608FD ModeFM=FEFE70E00605FD

So I may have solved this issue. The X6100 uses the name U-DIG not USB-D as in the settings on VarAC. So by changing the name in the Cat control .INI file to U-DIG, it looks to work. I think VarAC just couldn't find a USB-D so selects LSB otherwise. Maybe someone else would like to confirm this by edditing their INI file to confirm.