No GSM registration

Hi, i´m having the following problem with a great amount of Q2501B modules:

  1. The module works fine, registers on the GSM network and GPRS
  2. After several days in field(vehicles) GSM registration for a specific operator (TIM-Brazil) does not work anymore.
  3. GSM registration does work with other operator, but not with the first one, even after restoring factory settings (at&w) and using DWLWIN to rewrite OpenAT.
    PS: It happens in some modules, others work fine…

Are you sure this isn’t just due to poor GSM coverage?

Yes, because the same Sim Card works fine with some other modules and cell phones

Are you testing them all in exactly the same location?
Is that locatioin known for poor coverage?

With the other modules, are you using the same antenna?

What signal strength indication do the other modules and phones give?

Same place, same antenna. Not shure about the signal strength of the other modules. But the thing is that i register some(sufficient) GSM signal on the broken module, but there is no GSM registration.

Hi Sergio,

i have the same problem with TIM-BR (only TIM), with Q24PLUS !! However, when module is restarted the problem is solved. I have the same equipment with others operators without problem. Why ? I have no idea.


Hi hegler, do you find it possible that some module may be “out of frequency”? Since, as far as I noticed, the only difference between the GSM providers is the operation frequency(signal strength are pretty much the same).

Hi Sergio,

I think this is not possible. Since the exchange of band is only possible by command AT+WBSM and exchanged once it becomes permanent (written in Flash). In my case, after restart the equipment, everything become normal.