When I try to select another operator (for test purposes) from the list returned by AT+COPS=?, I either receive CME Error 30 or CME Error 32. For example, using a TIM Group SIM card:
AT+COPS=1,2,“72416”,7 //try to select “BrasilTelecom” LTE
+CME ERROR: Network not allowed emergency calls only
or
AT+COPS=1,2,“72405”,7 //try to select “Claro” LTE
+CME ERROR: Network not allowed emergency calls only
The same happens if I use a SIM card from other carriers. Do I need to enable roaming on the modem or something before trying to select an different operator?
IFAIK, national-level roaming is enabled by default on all carriers here in Brazil.