SIM card - IMSI used?

  • Hello,

    We are using a number of test SIM cards and noticed that IMEI is leading (we expected the IMSI to be leading).
    Now we are still in a test phase and it is not that important, however we are looking at live deployments as well.

    For real customers
    How do we block a customer? Using the IMEI only disables the device itself and does not disable the SIM card and its connectivity. So how does it work within TMO?


  • Deutsche Telekom IoT

    Good question!

    If you remove an IMEI number the sim-card will keep the possibility to attach to the mobile network. However

    • the network will not process the device data because the IMEI is not registered

    • there will be no cost-charging for it, because we only charge based on registered IMEI’s

    So removing an IMEI is the only thing you need to do to ‘block’ a connection.

  • Thanks Afzal,

    Do I understand correct that if you have an account only the registered IMEIs are costs-charged? So e.g. :

    • Somebody steals my SIM cards,

    • I deregister the related IMEIs in our account and we are no longer charged once deregistered

    • The thiefs could re-use the SIM card in their own TMO account and be charged for usage 🙂
      (and in the end we only need to get some new SIMs?)

    Is that how it works?

  • Deutsche Telekom IoT


    The thief can only re-use the sim-card when he registeres his own IMEI number and used the sim with his IMEI.

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