These are codes intended  to control peripheral devices (such as printers), or to provide meta-information about data streams, such as those stored on magnetic tape.
ðiːz ɑːɹ kˈoʊdz ɪntˈɛndᵻd tə kəntɹˈoʊl pɚɹˈɪfɚɹəl dɪvˈaɪsᵻz sˈʌtʃ ɐz pɹˈɪntɚz, ɔːɹ tə pɹəvˈaɪd mˈɛɾəˌɪnfɚmˈeɪʃən ɐbˌaʊt dˈeɪɾə stɹˈiːmz, sˈʌtʃ ɐz ðoʊz stˈoːɹd ˌɔn mæɡnˈɛɾɪk tˈeɪp.