If you really want to play around with this, start Googling for RS232 and ham radio stuff - they have been doing things like this for years. About the only pins available for you to directly control are the RTS and DTR outputs (RTSEnable and DTREnable). These you can set the state directly, and they will hold. You can test input states of CTS and DSR to detect their presence (CTSHolding and DSRHolding). As far as sending characters to perform actions, you would need external electronics to capture/decipher and act on the data.
