[Ovmsdev] 3G / 2G fallback on SIM5360 Europe?

Chris van der Meijden chris at arachnon.de
Mon Aug 3 18:31:41 HKT 2020


Hi Michael
yeah, economical visionaries are always a lot of fun :-))
I read that "GSM voices services" line too and checked on that with my
mobile phone. I restricted the connection of the phone with
*#*#4636#*#* to "GSM auto (PRL)" and it connects to EDGE. So data over
GSM is available ...
Still mysterious. Will dig some more ...
Greetinx
Chris 
Am Montag, den 03.08.2020, 12:21 +0200 schrieb Michael Balzer:
>     Chris,
> 
>     
> 
>     we don't tell the modem to restrict itself in any way. Bugs in
> the
>     modem firmware are likely, but I think a serious bug like this
> would
>     have been solved early.
> 
>     
> 
>     I've read the pilot description now, and you need to pay
> attention
>     to this section:
> 
>     
> 
>     
> > statt der üblichen drei Dienste LTE, UMTS
> >       und GSM kommen in Kirchfarrnbach "nur" LTE 800 und LTE 900
> > für die
> >       Datenversorgung sowie GSM für Sprachdienste und SMS zum
> > Einsatz.
> >       Auf UMTS haben die Funknetzplaner hier verzichtet, weil
> > bereits
> >       LTE und GSM alle Anforderungen der Bevölkerung erfüllen.
> 
>     
> 
>     …translated…
> 
>     
> > Instead of the usual three services LTE,
> >       UMTS and GSM, "only" LTE 800 and LTE 900 are used in
> >       Kirchfarrnbach for data supply as well as GSM for voice
> > services
> >       and SMS. The radio network planners have dispensed with UMTS
> > here
> >       because LTE and GSM already meet all the requirements of the
> >       population.
> 
>     
> 
>     So you have neither UMTS nor EDGE. GSM is only available for
> voice
>     streams and SMS. Data is only available via LTE.
> 
>     
> 
>     Your only option is to tell them they're a bunch of … outstanding
>     economical visionaries, who could possibly consider rethinking
> their
>     IoT compatibility ;-)
> 
>     
> 
>     Regards,
> 
>     Michael
> 
>     
> 
>     
> 
>     Am 03.08.20 um 11:33 schrieb Chris van
>       der Meijden:
> 
>     
> 
>     
> >       
> >       I did some more reading on the SIM5360 and also digged a bit
> >         through the simcom source. Found loads of AT-commands there
> > :-)
> >       
> > 
> >       
> >       I could not find an AT command to restrict the selection to
> >         2g. Perhaps I did not look deep enough, but if someone
> > knows the
> >         command ...
> >       
> > 
> >       
> >       I'm still thinking why the automatic fallback to 2g does not
> >         happen. 
> >       
> > 
> >       
> >       - The transmitter offers only 2g (GSM 900 mHz) and LTE (800
> >         or 1800). No 3g.
> >       - I have a signal strength of -110 to -100 dBm
> >       - AT+COPS? gives me an empty response.
> >       
> > 
> >       
> >       Could it be possible, that somewhere in the code something
> >         like
> >       
> > 
> >       
> >       - I don't have 3g
> >       - I do have LTE
> >       - Lets try LTE
> >       - I see LTE
> >       - I have no hardware for LTE
> >       - OK, don't do anything
> >       
> > 
> >       
> >       happens? So somehow fallback to 2g never happens?
> >       
> > 
> >       
> >       Just guessing around ...
> >       
> > 
> >       
> >       Regards
> >       
> > 
> >       
> >       Chris
> >        
> >       
> > 
> >       
> >       Am Montag, den 03.08.2020, 10:10 +0800 schrieb Mark
> >         Webb-Johnson:
> >       
> > > The SIM5360E should auto-switch between 2G
> > >         and 3G. It supports the following frequency bands:
> > >         
> > > 
> > >         
> > >         
> > >           GSM/GPRS/EDGE
> > >               850/900/1800/1900MHz;
> > >           UMTS/HSPA+
> > >               900/2100MHz
> > >         
> > >         
> > > 
> > >         
> > >         There are SIMCOM options/commands to restrict the
> > >           selection, but the default is automatic.
> > >         
> > > 
> > >           Regards, Mark
> > >           
> > > 
> > >             
> > > >               On 2 Aug 2020, at 6:40 PM, Chris van der
> > > >                 Meijden <chris at arachnon.de>
> > > >                 wrote:
> > > >               
> > > > 
> > > >               
> > > >                 
> > > >                 
> > > >                   Hey Michael
> > > >                   
> > > > 
> > > >                   
> > > >                   Thanx for the help :-)
> > > >                   
> > > > 
> > > >                   
> > > >                   The AT commands are working now, but as
> > > >                     expected no connection at all. So also no
> > > > fallback
> > > >                     to 2g. Or no GPRS offered on 2g ...
> > > >                   
> > > > 
> > > >                   
> > > >                   Here some (German) information on the
> > > >                     "site lite" transmitters:
> > > >                   
> > > > 
> > > >                   
> > > >                   https://www.telekom.com/de/blog/netz/artikel/
> > > > standort-light-pilotprojekt-552152
> > > >                   
> > > > 
> > > >                   
> > > >                   I also did not find any AT command for
> > > >                     the SIM5360 to force 2g. I will play a bit
> > > > around
> > > >                     with the modem in the next days. Will also
> > > > try
> > > >                     congstar, I do have a congstar SIM laying
> > > > around
> > > >                     here ...
> > > >                   
> > > > 
> > > >                   
> > > >                   Greetinx
> > > >                   
> > > > 
> > > >                   
> > > >                   Chris
> > > >                   
> > > > 
> > > >                   
> > > >                   
> > > > 
> > > >                   
> > > >                   Am Sonntag, den 02.08.2020, 10:59 +0200
> > > >                     schrieb Michael Balzer:
> > > >                   
> > > > >  Chris,
> > > > > 
> > > > >                     
> > > > > 
> > > > >                     how to send modem commands and read the
> > > > > responses:
> > > > > 
> > > > >                     
> > > > > 
> > > > >                     OVMS# log level debug simcom
> > > > > 
> > > > >                     Logging level for simcom set to
> > > > >                       debug
> > > > > 
> > > > >                     OVMS# simcom cmd AT+COPS?
> > > > > 
> > > > >                     SIMCOM command has been sent.
> > > > > 
> > > > >                     D (164488782) simcom: tx mcmd ch=4
> > > > >                       len=10  : AT+COPS?
> > > > > 
> > > > >                     D (164488792) simcom: rx line ch=4
> > > > >                       len=23  : +COPS: 0,0,"congstar",2
> > > > > 
> > > > >                     D (164488802) simcom: rx line ch=4
> > > > >                       len=2   : OK
> > > > > 
> > > > >                     
> > > > > 
> > > > >                     Now let's see if we have 3G:
> > > > > 
> > > > >                     
> > > > > 
> > > > >                     OVMS# simcom cmd AT+CPSI?
> > > > > 
> > > > >                     SIMCOM command has been sent.
> > > > > 
> > > > >                     D (164693462) simcom: tx mcmd ch=4
> > > > >                       len=10  : AT+CPSI?
> > > > > 
> > > > >                     D (164693482) simcom: rx line ch=4
> > > > >                       len=85  : +CPSI:
> > > > >                       WCDMA,Online,262-
> > > > > 01,0x16C3,7824927,WCDMA IMT
> > > > >                       2000,454,10836,0,7.5,104,18,8,500
> > > > > 
> > > > >                     D (164693482) simcom: rx line ch=4
> > > > >                       len=2   : OK
> > > > > 
> > > > >                     
> > > > > 
> > > > >                     Yes. Well, no surprise, Telekom network
> > > > > :-).
> > > > > 
> > > > >                     
> > > > > 
> > > > >                     The SIM5360 is supposed to automatically
> > > > > fall back
> > > > >                     to 2G if 3G isn't available. On a quick
> > > > > browse
> > > > >                     through the manual, I didn't find a
> > > > > command to force
> > > > >                     2G, just one to lock to a specific 2G
> > > > > cell… you
> > > > >                     could do that depending on your location,
> > > > > but maybe
> > > > >                     you should first inspect your modem
> > > > > status now.
> > > > > 
> > > > >                     
> > > > > 
> > > > >                     Regards,
> > > > > 
> > > > >                     Michael
> > > > > 
> > > > >                     
> > > > > 
> > > > >                     
> > > > > 
> > > > >                     Am 02.08.20 um 09:39
> > > > >                       schrieb Chris van der Meijden:
> > > > > 
> > > > >                     
> > > > >                     
> > > > > >                       
> > > > > >                       Hi all
> > > > > >                       
> > > > > > 
> > > > > >                       
> > > > > >                       I'm trying to understand some
> > > > > >                         principals of the SIM connection
> > > > > > methods of
> > > > > >                         OVMS.
> > > > > >                       
> > > > > > 
> > > > > >                       
> > > > > >                       Reason is that I recently moved from
> > > > > >                         "the big city" Munich to the very
> > > > > > much rural
> > > > > >                         village Thalham. In Thalham we have
> > > > > > so called
> > > > > >                         "lite" mobile transmitters. These
> > > > > > transmitters
> > > > > >                         are installed, as far as I
> > > > > > understood, to safe
> > > > > >                         money and to prepare the transition
> > > > > > of the
> > > > > >                         providers to 4g / 5g. They are
> > > > > > forcing the
> > > > > >                         frequencies towards the 4g band
> > > > > > with those.
> > > > > >                       
> > > > > > 
> > > > > >                       
> > > > > >                       So these transmitters seem to offer
> > > > > >                         only 2g and 4g, but no more 3g
> > > > > > (really ???).
> > > > > >                       
> > > > > > 
> > > > > >                       
> > > > > >                       I don't have any network connection
> > > > > >                         with the SIM in my OVMS here in
> > > > > > Thalham. In the
> > > > > >                         next village Zolling I have
> > > > > > connection. In
> > > > > >                         Zolling they don't have the "lite"
> > > > > > transmitters,
> > > > > >                         but still have full 3g support. The
> > > > > > antenna of
> > > > > >                         my OVMS is working well (-100 dBm
> > > > > > to -70 dBm).
> > > > > >                       
> > > > > > 
> > > > > >                       
> > > > > >                       Now my questions ...
> > > > > >                       
> > > > > > 
> > > > > >                       
> > > > > >                       Does OVMS have a fallback on SIM5360
> > > > > >                         Europe to 2g (EDGE) if 3g is not
> > > > > > available?
> > > > > >                       
> > > > > > 
> > > > > >                       
> > > > > >                       I also did some reading in the modem
> > > > > >                         documentation and tried to send
> > > > > > some AT
> > > > > >                         commands. Goal is to try to force
> > > > > > the SIM into
> > > > > >                         2g mode. I tried i.e.
> > > > > >                       
> > > > > > 
> > > > > >                       
> > > > > >                       simcom muxtx 2 AT+COPS?
> > > > > >                       
> > > > > > 
> > > > > >                       
> > > > > >                       to get some information from the
> > > > > >                         SIM, but I don't get an answer on
> > > > > > that command
> > > > > >                         at all. No matter what channel I
> > > > > > try. Am I
> > > > > >                         missing something there?
> > > > > >                       
> > > > > > 
> > > > > >                       
> > > > > >                       Thanx for input.
> > > > > >                       
> > > > > > 
> > > > > >                       
> > > > > >                       Regards
> > > > > >                       
> > > > > > 
> > > > > >                       
> > > > > >                       Chris
> > > > > >                       
> > > > > > 
> > > > > >                       
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