ðɪs ɪz kwˈaɪt kˈɑːmən ɪn kəmˈɜːʃəl pˌiːˌiːpˈiː dɪvˈaɪsᵻz, wˌɪtʃ ˈækt æz ɐ blˈæk bˈɑːks, jˈuːzɪŋ mˈoːɹ ɔːɹ lˈɛs ˈoʊpən pɹˈoʊɾəkˌɑːlz tə kəmjˈuːnᵻkˌeɪt bᵻtwˌiːn ðˌɛm ɪnðə plˈeɪs ʌv tˌiːsˌiːpˈiː.
This is quite common in commercial PEP devices, which act as a black box, using more or less open protocols to communicate between them in the place of TCP.