multiple device support with Gobi API


I am wondering if I can access multiple MC9090s with GOBI api. I have a system where there are 6 MC9090s which are managed by an embedded linux operating system. Currently I am using AT commands to configure and manage these modems but I was told by sierra people that MC9090 doesn’t support switching between CDMA and 3G modes via AT commands.
I remember that the sierra linux sdk doesn’t support managing multiple modems at the same time. Is this the same for Gobi Api?

Thanks a lot for your time

What kind of application require 6 MC9090s con-currently? :smiley:

Anyway, multi-device support in Sierra QMI sdk will be available in next release.

Please ping your contact in Sierra to know the exact schedule.

Hello Lotam,

Thanks for the answer. We are using 6 MC9090s for transmitting real time video data. The system runs an algorithm which checks the bandwidth of each modem and distributes the payload dynamically. MC9090 is important for us because it supports both CMDA and 3G. But so far I wasn’t able to make it switch between these technologies. Regarding my sierra contact, it may be my bad luck but I have always experienced huge delays for getting some answers ( I am talking about months:// ) so if you have any estimates regarding this new release I would be most happy to hear it.

Also if there are any alternatives to switch modes in MC9090 I would be most happy to hear it.

Thank you a lot for your guidance

If you don’t want to wait for the new SDK, then there is always the open source libqmi alternative:

It might be a bit heavy for embedded platforms with all its dependencies, and it might not hold your hands as much as the Sierra/Qualcomm SDK, but at least it doesn’t have any problems using a large number of modems. Uhm, yes, and it uses the mainline qmi_wwan driver which means that you are out of luck if you depend on older kernels. And obviously I’m biased, not liking out-of-tree drivers or binary blob libraries all that much :slight_smile:

What’s the exact problem?
Actually, sample application Gobi Image management is available in Linux QMI SDK for such purpose.

Hope it helps.

Hello dl5162 :slight_smile:

Thanks a lot for your suggestion. I didn’t know about open source libqmi alternative. I have checked it but as you’ve also said, it doesn’t support the kernel that I am stuck with at the moment. I have suggested upgrading the kernel we use in our products. If I can convince them I’ll give this a try.

Hello Lotam

As you’ve pointed out we were able to switch between CDMA and 3G modes via the Gobi image management in linux qmi sdk however the sdk supports a single modem hence we have thought that we can’t proceed on this path. With the AT commands, we weren’t successful.

About this new release that you’ve talked about. I have seen the Legato platform on Sierra webpage. If I become a beta tester, can I get the new sdk that supports multiple modems?

Thanks a lot for your help

Hello Lotam,

Sorry to bother you again with double posting but if it’s possible, can you please confirm about the legato question that I have asked in my previous post?

Legato is for another product line, AR/WP series:


Thanks for the reply. I read about legato before and saw what you said but still thought that the new SDK you’ve talked about could be in it. New product, new SDK :smiley:
Anyway, if this isn’t the case, I guess I just have to wait until it is announced on the webpage.

thanks again for your help


A new Linux QMI SDK release has been posted on the tradition SharePoint repository. This is an alpha release of the coming 3.3… which is including the multiple module management.


Hello Jacques,

Thanks a lot for your tip. Can you also please post a link to that sharepoint repository. I wasn’t able to find it on the website. I am quite excited about this new release. Hopefully all our problems will go away:)



sorry to double post again but, I have been looking for this sharepoint repository for the alpha version of linux qmi SDK to no avail. Is this something that we should request from Sierra. If anyone can guide me about this I would be most happy.

Thank you very much

Hi rt,

Please check with your distributor or FAE in contact to create access account on sharepoint for you, so you can get the QMI SDK from there.


Hi Lotam,

Thanks for your feedback. I’ve just contacted my FAE. I’ll report how things go here so that others can also benefit.

Have a nice day