Using Hologram hardware and SIM in South Korea

Ok, there are a number of threads here about this, but none of them are really helpful. I am in South Korea at the moment and the hologram SIM card does not work here. I do some of my development remotely with partners in the US. The whole hologram stack works ok there, but that is not sufficient for us. I need some connectivity here as well as being able to use an alternative SIM whenever the hologram one does not work.

I can handle losing the hologram cloud infrastructure in the cases that I run a backup SIM. What I want is to use the ublox modem directly when that happens. How do I send AT commands to it from the Arduino enviroment (Is that what Serial1 is connected to)? I understand that the firmware assumes that it has complete control over the ublox, but surely if I never use any of the Dash.() API (Dash.begin() etc…) then there should not be a conflict.

Alternatively, is the firmware source out as promised, maybe together with build instructions?

Thank you for your time.

Ok, I would like to add some information here. I missed it at first when reading the docs, but Hologram actually made it incredibly easy to talk to the ublox modem directly. It is documented here:

Basically, call HologramCloud.enterPassthrough(); in setup() and SerialSystem is then a direct serial connection to the modem. For example, a call with


results in:


kudos to hologram!

I don’t know how which commands to send to the ublox to change the SIM card configuration yet. If anyone has any info at all, I would appreciate the input. If I figure it out, I will share here…

Hey @janbbeck, we’d actually like to help figure out why there isn’t coverage there. We have carriers that are on our network in South Korea. Could you tell us more about the hardware you’re using? It’s possible that the hardware working in the states won’t work over there because of different bands being used.

Thank you for offering to help. I am using a hologram Dash.

I did add a check for signal strength to the helloworld example. It reads 99. I drove around town for a while. No change.

Ah, sorry, I should have asked sooner, what is the number on the uBlox modem? Is it a u260? Or a u201? Or something else?


Well, good news and bad news:

The good news is, we have figured out the problem.
The bad news is, that part is only for the US.

Our newer dash uses the u201 which is global.. But this explains why it is working for your US co-workers and not for you. I’m sorry about that.

Ok, I have a MKR GSM 1400 on order, which has a U201. The hologram SIM will work with that then, right?

Correct. If you have issues getting online with that hardware, please start a new thread. Thanks!

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