External SIM option for B SOM's

We have project where we need to mount an external SIM with a B523/B524 on a few units, like it is possible with Boron.

At the same time the internal SIM currently seems nearly impossible to activate/deactivate, from the console and even for support. The back-end with the MVNO seems to be broken. Not cool when your are locked in.

Looking at the B523/B524 data sheet, the SIM connections are broken out on the pins. But the schematics are not available so, is there a dual sim switch onboard, or would the MFF2 need to be desoldered to use the external pins for a SIM?

Alternatively, is it possible to transfer the ICCID to another MVNO, as is easily done for a mobile phone?

Hi there - just want to quickly speak to the issue around B523 SIMs. The B523 SIM provider has been experiencing a number of technical issues recently, and we are working hard with them to rectify the situation. Totally understood that this is a rough experience.

B524s should not have SIM issues however - EtherSIM provides us with much more immediate agency around SIM state.

ICCID transfer is not a possibility here, and an external SIM solution does require desoldering.

May I ask - apart from the poor performance of B523 SIM state management, what motivates the 3rd Party SIM route? Are you attempting to deploy in an unsupported region? If so, where?

Thanks. EtherSIM do seem to be a huge improvement on coverage.

This is for a prototype for a number of Arab countries, known to be “difficult” for outside MVNO’s. So currently hand over ICCID’s or plug their SIM in.

It is an unsupported region at this time, but this project is early stage.

Future regulation will set IoT E-SIMS free, and i am guessing PIO’s current payment model has taken this somewhat into account. It would not take much away from PIO being payed based on operations.

In the mean time, these countries could wake up and notice, that in a world of locked E-SIM’s, they could be left behind in the IoT technology space.

Software wise, we can set external sim APN in SW as with borons?

The B Series SoM is not intended to be used with a 3rd-party SIM card. As you’ve noticed, there are pins on the M.2 labeled for this purpose, but they do not work.

There are four 0201 SMD 0-ohm resistors on the top of the B Series SoM module on the right (with the M.2 at the bottom). If you move these resistors the M.2 SIM pins will work. However, this is not recommended, voids the warranty, and of course is extraordinarily tedious to do this with more than a few units. It is not possible to buy a B Series SoM with external SIM enabled.

If you have a base board with a 4FF SIM card socket and a modified B Series SoM, you can set the APN the same way as other devices.

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