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Toggling Technologies on a SIM

You can change which cellular technologies the network will allow the device to connect to.

Jakub Kubinski avatar
Written by Jakub Kubinski
Updated over a month ago

You can turn on and off different technologies at a network level, per SIM. This will result in the device being denied if it tries to connect using a disabled technology.

What are the technology options?

  1. SMS

  2. 2G / 3G

  3. 4G

2G / 3G cannot be separated.

How to edit enable / disable technologies on a SIM

  1. Go to the individual SIM page in the Onomondo App.

  2. Click the "Edit" button on the left side panel.

  3. Choose technologies to be allowed and click "Save".

We recommend testing this feature thoroughly before rolling it out to deployed devices. Your device may behave unexpectedly.

Guidelines for implementation

It is strongly recommended to disable technologies when the device is offline to avoid undesirable and unexpected behavior. Disabling a technology while a device is connected using that technology can sometimes cause issues. Test it out to ensure this case is correctly handled in the firmware. In most cases, the device will simply be ‘kicked off’ and can immediately start attaching to an available network.

The time to attach after updating allowed technologies may increase, as the device may attempt to connect to technologies that are not allowed. This only occurs the first time, as the last known ‘good’ network is saved by the modem, and subsequent attempts will use this information.

The modem has been observed to be attached on the GSM network even though all technologies are disabled on a SIM level.

AT+CREG?
+CREG: x,5

Ensure this is correctly handled in the device firmware, as the modem will not be able to activate a PDP context. If relying on CREG for registration status, this can cause the device to end up in an unintended state.

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