What is the correct procedure for changing the APN settings in operation?
The plan is as follows:
the device is active and works with sim card 1 and APN settings 1 .
The device is switched off and the SIM card is replaced.
The APN settings are sent by SMS to the number of SIM card 2.
The device switches on, receives the SMS and sets the new APN settings.
I have tried this out. However, the login to the network is denied because the module still uses the APN settings of SIM card 1, even if the APN settings are not actively set after switching on the module. SMS is therefore not received and new APN settings cannot be used.
I have now solved this as follows:
the APN settings for PDP Context 1 are always
AT+QICSGP=1,1,“”,“”,“”,0.
This means that the connection to the mobile network is always successful and SMS reception also works.
Context 2 is used to transmit the data via HTTP where the received APN settings are used. This also ensures the data connection works. I have tested this with Telekom and Emnify cards.
Is this procedure OK or is there a better way to solve this?