= 3 ) { modem.simUnlock(GSM_PIN); } // 2 Automatic , 13 GSM only , 38 LTE only , 51 GSM and LTE only String res; do { res = modem.setNetworkMode(38); delay(500); } while (res != "OK"); do { res = modem.setPreferredMode(1); delay(500); } while (res != "OK")...