RTS_CONTROL_HANDSHAKE top-level constant
Enables RTS handshaking. The driver raises the RTS line when the "type-ahead" (input) buffer is less than one-half full and lowers the RTS line when the buffer is more than three-quarters full. If handshaking is enabled, it is an error for the application to adjust the line by using the EscapeCommFunction function.
const RTS_CONTROL_HANDSHAKE = 0x02;