The ContinueXMitOnXOff property specifies whether data transmissions continue when the receiving buffer is close to full ...

The ContinueXMitOnXOff property specifies whether data transmissions continue when the receiving buffer is close to full and an XoffChar character has been sent to the transmitter.
Values: TRUE or FALSE. If TRUE, transmission continues after the input buffer has come within XoffLim bytes of being full and the driver has transmitted the XoffChar character to stop receiving bytes. If FALSE, transmission does not continue until the input buffer is within XonLim bytes of being empty and the driver has transmitted the XonChar character to resume reception.