Error: Invalid number format while sending SMS with SIM800L

Question

I'm using a SIM800L GSM module connected over USB-Serial to my computer. When I try to send a SMS I got an error:

AT+CMGS="+4915xxxxxxxxx"
> Test (Ctrl+Z)
+CMS ERROR: Invalid number format (incomplete number)

I’m obviously connected to the network because pin is entered +CREG an +COPS seems good.

AT+CPIN?
+CPIN: READY

OK
AT+CREG?
+CREG: 0,1

OK
AT+COPS?
+COPS: 0,0,"O2 (Germany)"

OK

As well I can receive SMS and see incoming calls. I set the module in sms text mode and use the coding GSM

AT+CMGF?
+CMGF: 1

OK
AT+CSCS?
+CSCS: "GSM"

OK

I try different number formats like "015xxxxxxxxx" or "004915xxxxxxxxx". Also I try different values for the optional parameter from +CMGS

Could anybody advise me what to do?

Answer 1

To send SMS it was necessary for me to change the SMSC adress with the command AT+CSCA.

AT+CSCA="+491760000443",145

The SMSC you can found at your mobile operator. In my case Netzclub at O2 Germany.