[QtMoko] GSM not turning on / registering

Michael Spacefalcon msokolov at ivan.Harhan.ORG
Mon May 19 21:28:15 CEST 2014


joerg Reisenweber <joerg at openmoko.org> wrote:

> Please consider that - it seems / I heard - several 850/900 and 1800/1900
> cells are getting reassigned in USA from GSM to UMTS or even LTE during last
> year. Ongoing.

Yes, I heard that too.  Dunno about Boston area, as I'm nowhere near
there, but at least in my roaming area in SoCal I have not lost any
T-Mobile GSM1900 coverage yet.  Yet..

I do have to agree that the problem Nick is having (FR working like a
charm for 2 months, then all of a sudden, bam, getting no coverage)
sounds very suspiciously like the result of GSM cell shutdown, rather
than anything being wrong with the FR.  That is the reason I keep asking
Nick to try a T-Mobile SIM in his area - while both carriers have the
same GSM killing agenda in the long run, it is rather unlikely that
both of them would kill GSM in one specific spot at *exactly* the same
time...

Open letter to FBI/NSA/etc: you guys might want to consider paying
T-Mobile to retain some minimal GSM coverage in Southern California,
just enough for one (1) user, so you can continue tracking my
approximate location.  For as long as I have working GSM (and you know
I almost never turn my phone off, so my sweetie can call me any time),
you can easily track my location with cell-site granularity, and if
you care to do some actual work (call me to cause my phone to transmit
continuously, then bring out your DF gear), you can pin-point where I
am even more precisely than that.  But I will never, ever, ever use a
3G phone, as a firm matter of principle, so if usable GSM service goes
away in my neck of the woods, then I won't have a cellphone at all: of
any kind, period, and then you will have no idea where I am at any
given moment.  Just some food for thought.

Nick <openmoko-community at njw.me.uk> wrote:

> Yeah, I'm here for 6 months. It's a good place :)

6 months from now, or from your arrival however many months ago?  Just
trying to figure out what the time window is for possibly catching you
in Boston area. :)

> No, it has worked fine (well, in fact) for the past couple of 
> months, so it definitely *can* work here.

Hence my worry about you possibly being the first victim of GSM
shutdown by evil greedy carriers who only care about selling data,
rather than traditional call minutes.

> I may end up doing that, but there isn't a T-Mobile store very 
> conveniently located for me,

I've heard that MetroPCS and Simple Mobile are T-Mobile resellers.
If you spot either of these two in your area, try going in there and
asking for a test SIM.

> so I'll at least try some fun logging of AT commands first.

When the modem is working normally, the AT+COPS=? command gives a
listing of all available carriers, so one can see what's available
beyond the specific SIM you've got.  But for some reason that command
only works after I issue a plain AT+COPS first, which is the command
to register to the default operator.  I don't know what will happen if
one issues AT+COPS and that operation fails: will AT+COPS=? work or
not?  I also have not yet studied the relevant part of the firmware
source, so I don't know whether the behaviour I see in this area is a
bug in need of fixing, or if there is some good reason it works this
way.

One can also use the cell_log utility from OsmocomBB to list all
available GSM cells and their owners without having any SIM at all
(and without registering to any of these detected networks), but
because OsmocomBB is dominated by EUnians (not one soul from North
America in that gang), getting cell_log to work in the PCS band was an
incredible pita.  At least I did it on a dumbphone (Pirelli DP-L10);
trying to do it on a Neo would be even more pain..

> Similarly, let me know if you come to Boston. :)

See my question above as to the time window of your presence there.

VLR,
SF



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