Hi Yevhen, I've seen the same issue before with an Huawei modem. It looks like not all modems can handle sending "ATE0 +CMEE=1" to the modem and pcui port simultaneously. Try removing this line from huawei_enable(): g_at_chat_send(data->modem, "ATE0 +CMEE=1", NULL, NULL, NULL, NULL); Regards, Cedric