Is there any “defined” behavior for these signals?
Say, I have an application which provides “transparent” TCP connection from serial port. It connects to TCP server and then switches FCM port into data mode. When in data mode, there are some events wchich can be interepreted as “NO CARRIER” or so. Instead of switching into AT mode and write “NO CARRIER” one can just deactivate DCD signal, but this is impossible.
So the question is: can we assume that DCD signal reflects just FCM port state (say, on for data mode, off for AT mode), or DCD state can be explained otherwise?
The same question is about flow control signals: is there any strictly defined behavior of those signals when port is subscribed to FCM flow?