BGS2T (BGS2-W) CSD call to roaming/SIM in other jusistriction | Telit Cinterion IoT Developer Community

Hi,

I'm trying to make a CSD call from a BGS2T terminal (REVISION 01.301) (2G) to another terminal which has either a roaming SIM in the same jurisdiction or a local SIM in a different jurisdiction. I know that CSD's days are numbered but we have legacy systems or some clients that insist on it still. I very quickly receive only 'NO CARRIER'. I can call other CSD SIMs without issue.

I've tried variations of the number format eg:

ATD0**********

ATD00CC**********

ATD+CC**********

Should these make a difference?

What format should be used for a MSISDN number which starts 34590? Does it make any difference?

ATS18=1

gives:

+CAUSE: 8:57

{GSM cause for L3 call control: bearer capability not authorized}

I wonder if this refers to CSD or calls to a roaming SIM or one in another jurisdiction?

Or is this a problem of the bearer not being supported by intermediary networks?

The modem is only changed from factory defaults by the use of:

ATX0

ATS0=1

ATV1&C1&D2+CBST=0,0,1

(+CBST made no difference but is another thing I tried)

I also wondered if there is a bar on roaming, or calling out of the jurisdiction in the terminal, because the SIM provider tells me that the call attempts are not getting to the network.

AT+CLCK="SC",2

+CLCK: 0

{no SIM lock}

AT+CLCK="FD",2

+CLCK: 0

{no fixed dialing lock on a list of numbers, which sounds as though it could have caused this issue if it had been enabled}

I’m just getting ERROR in response to other lock inquires though?

AT^SPLM

{returns very long list of network operators}

AT+CPOL?

{returns a list of 15 operators}

Any advice welcome, and happy to test/debug.

Best Wishes,

A