I need to be able to drive the Ring Indicator pin (SUB D9 - Pin 9) in the Serial COM port. I am using MS Visual C++ and already use the EscapeCommFunction to Set and Clear DTR & RTS for my purposes. However this does not allow you access to RI. I know that I can monitor for events on RI but I need to drive it. I have spent quite some time searching the web for ideas but without success. Anyone out there who can help me please?