====== AT команды ======

=== Список текущих операторов ===
  at+cops=?
  +COPS: (1,"MegaFon RUS","MegaFon","25002",2),(3,"Beeline","Beeline","25099",2),(1,"MTS-RUS","MTS","25001",2),(3,"","","25020",2),,(0,1,2,3,4),(0,1,2)
  OK

=== Установить APN ===
  AT+CGDCONT=1,"IP","internet"