Every cellular connected device has an IMEI (International Mobile Equipment Identity) number which is used to identify the hardware that is being connected to the network. This is very useful when it comes to mapping SIMs to specific devices and detecting when a SIM is being used in a new device given that we can always trace a Hologram SIM using the Dashboard and determine what device it's being used in by viewing session data as described in this guide.

On top of that, the Hologram Dashboard has built in IMEI detection that keeps track of the IMEI used with the SIM. This takes place in the console/logs section of the Dashboard and is triggered under the following circumstances:

  • When a SIM is first connected by sending a message and attaching an _IMEI_FIRST_ tag
  • When a SIM is connected using a different IMEI compared to the previous session by sending a message describing the change and attaching an _IMEI_CHANGE_ tag
  • When a SIM is connected using a different modem model (different IMEI and TAC) by sending a message describing the change and attaching an _IMEI_TAC_CHANGE_ tag 

Note that the difference between an _IMEI_CHANGE_  and an _IMEI_TAC_CHANGE_  is that in the first case the Type Allocation Code (TAC), (the initial eight-digit portion of the IMEI) is the same in the old and new IMEIs indicating that the device is different, but uses the same type of modem. In the second case the IMEIs are entirely different which indicates that the SIM is being used in a completely different device.

Setting up an automated IMEI change alert is then as simple as creating a new Route that triggers an action when either of the three tags is detected. This guide goes over that process.

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