Using the external SIM slot
The following two conditions must be met to activate communication via the external SIM card:
- The SIM card must be inserted in the external SIM slot (see Inserting/replacing the SIM card)
- The APN settings (APN, username and password) and the PIN code (if required by the SIM card) for the inserted SIM card must be transferred to the 4-Channel Data Logger using the DeviceConfig configuration program (see "GSM" tab) .
In the current implementation, using an external SIM card will not increase availability. This means that in the event of any communication problems relating to the external SIM card, the firmware will not automatically switch to the internal SIM chip. This cost-oriented approach helps to prevent any resulting charges for using the internal SIM chip as soon as the external SIM card has been activated.
To reactivate the internal SIM chip, it will not suffice to remove the external SIM card from the SIM slot. The APN settings must also be deleted from the 4-Channel Data Logger using the DeviceConfig configuration program.
The following table specifies under which conditions the external SIM card or internal SIM chip is used. The parameters are checked each time the modem is activated."‑‑‑" indicates a state where it is not possible to establish a connection.
| External SIM slot released | External SIM card inserted | Correct APN setting saved in the device | SIM used |
|---|---|---|---|
| 0 | 0 | 0 | internal |
| 0 | 0 | 1 | --- |
| 0 | 1 | 0 | --- |
| 0 | 1 | 1 | --- |
| 1 | 0 | 0 | internal |
| 1 | 0 | 1 | --- |
| 1 | 1 | 0 | --- |
| 1 | 1 | 1 | external |
