By observation, all computer programs, all codes (TCP/IP etc.) and all symbolic communication systems outside the realm of life, (radio, tribal drum beats, thermometers etc) are all ultimately designed by conscious minds.
If you constrain your observations to only man-made codes and communication, then you are, by definition, only going to see codes made by conscious minds.
If you include thermometers, then you're opening a whole new can fo worms. What about a water hole that raises and lowers based on atmospheric pressure? It's sending us messages about the atmospheric pressure, but it wasn't created by a conscious mind.
Communication is not only created by conscious minds...animals communicate. If you say that animal communication is dictated by DNA, then so is human communication, which includes all the codes we create, so it then looks like all codes are natural and none are created by an intelligence.
Your biggest problems in this thread are conflation and misunderstanding your own definitions.