Problems with ELS62 and transparent socket connection while using roaming sim-cards

Cellular Modules
1

We use a ELS62 with a “1nce”-simcard.
The 1nce simcard is a roaming sim card, so we dont set a operator.
The only parameter we have to set is the apn.
We work with “at+cops=0”. The ELS62 connects in the automatic mode to a telefonica “in germany 26203” cell.
Afterwards we are establishing a transparent socket connection. So far so good. While our application is sending data after a few minutes the ELS62 changes the provider to a telekom cell “in germany 26201” for no reason.

After that the ELS62 no longer take responses to “+++” for leaving the transparent data mode, or “at-commands” to do a reestablish of our socket connection.
After turning the power off and on, the els62 works again.
Do anyone unterstand this behavior?

We are using the following firmware:
ati1
Cinterion
ELS62-W
REVISION 01.200
A-REVISION 01.000.04

OK

2

Hi Daniel,

Thank you very much for your message and all the details about your issue.

Could you please verify which interface you are setting the transparent mode on? Also, could you check if the Multiplex Mode (MUX) is enabled? I am asking that since, as noted in the most recent ELS62 Release Note (available for download on Telit Cinterion Download Zone), transparent mode is not fully supported on the USB/MUX ports.

If you are using USB/MUX could you please perform a similar test on the serial interface (ASC0) with MUX disabled?

Best Regards,
Karol