How to read IMSI number from SIM

[Ethan]

I try to obtain from IMSI number for a GATT Characteristic. However, by using AT+CIMI it returns valid result only after network connection established. 

Could you please let me know how to read IMSI number from SIM card?

[awneil]

IIRC, it isn't stored on the SIM - it's an association that's managed within the network ?

[Ethan]

Thank you for your response. 

I am not sure about it. Since I can read IMEI number, I thought IMSI can be readable as well.

[awneil]

IMEI = International Mobile Equipment Identity (or Identifier); it is embedded in the module - not the SIM. 

A different SIM could be inserted, and the IMEI would remain the same.

IMSI = International Mobile Subscriber Identity (or Identifier); it identifies the service "user".

AT+CCID should give you the SIM card serial number (ICCID) - which the network associates with the IMSI

 

[Ethan]

I would like to confirm whether there is any conditions in order to acquire IMSI. 

For example, when I use AT+CIMI to acquire IMSI, it returns valid result only when the network connection is established, which means acquisition of IMSI requires a network connection. 

Please confirm. 

[Håkon Alseth]

Hi,

 

Query the SIM just after enabling the modem (CFUN=1), as the power to the SIM card is normally turned off to ensure low power consumption, especially in sleep modes (eDRX/PSM). Alternatively, you can issue AT+CFUN=41.

 

Kind regards,

Håkon