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V by Vodafone

Can't send SMS messages using a GSM/GPRS module

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1: Seeker

Hi! I've just got a V-Sim and activated it to use with a small development board using Quectel MC20 GSM/GPRS module. Generally speaking everything works fine, I can activate GPRS context, open TCP connections etc. One small problem I've got is with sending SMS messages...

 

The module receives messages from the V app (aka "commands") - I can read them all right. But when I try sending a message, I get "CMS ERROR: 21", like this:

 

AT+CMSS=1
+CMS ERROR: 21
AT+CMSS=3
+CMS ERROR: 21

In the above example I've tried sending the message to both my normal (non-Vodafone) UK number, and to the slightly weird "123456" I get the "app commands" from:

 

AT+CMGL="ALL"
+CMGL: 1,"STO UNSENT","07xxxxxxxxx","",,129,20
TestToNormalUKNumber

+CMGL: 2,"REC READ","123456","","2019/10/13 23:52:06+08",128,18
TestCommandFromApp

+CMGL: 3,"STO UNSENT","123456","",,129,12
TestTo123456 OK

Perhaps the plan I've chosen ("Generic Tracker" as that's what the device I'm prototyping is supposed to be) doesn't allow me to send SMS messages at all? If so, which one should I switch to in order to be able to do so? It's not a crucial functionality for that little project, but I simply don't like not understanding what's going on :-)

 

One thing I've noticed is that the device reports it status as "Registered, roaming":

AT+CREG?
+CREG: 0,5

OK

so perhaps that's why the SMSC number

AT+CSCA?
+CSCA: "+316540967011",145

OK

looks Dutch? Or perhaps I simply somehow got it wrong and that's why my outgoing messages are failed? The CMS error 21 is documented as "Invalid index" which doesn't tell me much... Note that when I changed SMSC to Vodafone UK's (+447785016005), I was getting CMS error 28:

AT+CSCA="+447785016005",145
OK
AT+CMSS=1
+CMS ERROR: 28

which seems to mean "Unidentified subscriber" - that would suggest that indeed V-Sim is not really considered a Vodafone UK subscriber module...

 

So, am I doing something wrong, am I missing something, or is this the "correct behaviour"?

 

Regards and thanks for any help!

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