Many of the control codes are still in active use today in the air-ground communications protocol spoken between airplanes and Air Traffic Control.
The ACARS[0] protocol I work with every day starts each transmission with an SOH, then some header data, then an STX to start the payload, then ends with either an ETX or an ETB depending on whether the original payload had to be fragmented into multiple transmissions or fits entirely into one.
These codes aren't archaic and obsolete in the embedded avionics world.
[0] ACARS: "Aircraft Communications Addressing and Reporting System" - see ARINC specification 618[1]