Sierra Wireless EM7455

Dan Williams dcbw at redhat.com
Thu Aug 4 16:50:08 UTC 2016


On Thu, 2016-08-04 at 17:13 +0200, Nicolas Christener wrote:
> Hi Dan :)
> 
> On Wed, 2016-08-03 at 11:09 -0500, Dan Williams wrote:
> [...]
> > 
> > Any chance you can try the SIM in another WWAN card in the
> > computer, or
> > in a USB stick?  Or try the same EM7455 in Windows?
> tl;dr: the WWAN card works now! It might to be related to the SIM
> PIN.
> 
> Longer description: I bootet the Thinkpad with a USB stick that has a
> Windows
> 8.1 on it (this Windows version is not related to the Thinkpad and
> e.g. does
> not contain device specific drivers, etc.).
> 
> While Windows showed a "mobile broadband" (or similar) icon in the
> network
> settings it did not connect out of the box. My suspicion was, that I
> probably
> need to set my SIM PIN and other ISP related data somewhere.. while
> searching
> for the right place in Windows where I can set this information I
> found an
> option to remove the PIN from the SIM. I did so, but Windows still
> didn't
> connect (no error message was shown and I didn't investigate much).
> 
> I rebooted the device and without any further change I can now
> connect to the
> Internet using ModemManager/NetworkManager/etc.
> 
> I had a Thinkpad T520 with an Ericsson (IIRC) WWAN card before. The
> SIM card
> was a micro SIM and it was PIN protected as well. I did a 'dd' of the
> whole
> disk to the new device but had to replace the SIM as the T460s uses a
> nano
> SIM. So the PIN stuff worked on the old device, but there might be an
> issue
> around MBIM (just a wild guess) that prevents ModemManager to use/set
> the PIN
> on the new device?

MBIM should work OK with a SIM PIN; also while your connection
configuration had a PIN specified, it wasn't used because the modem
didn't need one.  However, when you "removed the PIN from the SIM" did
you have to enter any PIN at all?

What I think is happening (and Aleksander can correct me if not) is
there can be some provisioning data that is downloaded from the
operator to the SIM and/or device when it registers with the network.
 Maybe the modem was never in an idle state long enough to do that, or
maybe Windows knows how to do something MM doesn't...  that's my best
guess at least.

Dan


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