Quectel: Allowed modes

[Fredrik Flornes Ellertsen]

>
> Hey,
>

> I would assume that sending SSSP message with the Network Selection
> Preference TLV (and only that TLV) is what we should be doing, yes.
> That's what I understood from the Initiate Network Register
> deprecation notice, at least.
>
>
Hi Aleksander,

We have now tested this change on a few devices and initial results are
promising. Thank you for your help.

I was hoping you could help us with another issue regarding the Quectel
BG96 modem. Around half of our devices experience intermittent modem
crashes where the four USB devices presented by the modem disappear from
the host. The modem usually re-enumerates after a few seconds with no
issues. Some devices are more prone to this failure, which can cause
significant downtime on the cellular connection.

We have done extensive testing of the rails lines in the system and are
fairly confident this is not an issue with power supplies. It also happens
regardless of the modem's connection state -- this has happened on
unconnected devices (in RF boxes) as well as devices connected on 2G, and
LTE. We have a running thread with a Quectel FAE but nothing conclusive has
been determined.

This is probably a long shot, but have you seen similar behavior before? If
not, do you have a gut feeling as to what might cause such crashes?

Thanks for all your help.

Best,
Fredrik
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