Sim900 list of operators question

Hi friends!!
I'm on holiday :slight_smile: and i'm working on sim900 shield module.
my question is:
why if i execute AT+COPS=? i'll got only this response :
+COPS: (1,"vodafone IT","voda IT","22210"),,(0,1,4),(0,1,2)
only one operator............

but if i use a phone i can call other operators ?????

thanks for a response.

You can call any number but can you join any operators?

If I remember correctly the command returns the list of networks that are avaialble to connect to (ie your contract is valid to join that network)

i'll try to explain it.
If i use a sim900 shield i can use only vodafone operator to receive calls.
In fact if i use AT+COPS=? in hyperterminal without sim card returns :
+COPS: (1,"vodafone IT","voda IT","22210"),,(0,1,4),(0,1,2)
if i try to use other operator like TIM or ILIAD can't connect to network.
But... if i insert TIM or ILIAD in a smartphone i can receive and make calls.

I know that sim900 shield module use 2g,4g ........ now i'll check if is a type of network problem.