I am studying a system running a serial connection and looking not to intercept its packets, but merely to inspect the traffic as it passes.
Hook the RX and TX wires to the RX of two serial channels on my Arduino. Read the messages sent in either direction separately. Don't know the baud rate so this might be experimental?
Split the connection, absorb both sides of the break into a RX TX serial connection on the Arduino, and set up forwarding from each to the other while inspecting the content.
In either option I can see the need to inspect the connected wires and establish the highest observed baud rate to match to. In the second option until I inspect enough data to reliably get the baud rate, data will be lost unless it is buffered.
Has anyone got any experience with a situation like this?