SIM900 - No registration to network and strange band returned

[hotkebab99]

Hello,
I have bought recently a SIM900 shield. I can send to it AT commands and I have the answers.
The problem is that it can't register to the network. I live in France and I have tried with 4 SIM cards from different operators ; always the same. I have plugged a good power supply to the shield (5V - 5A max).

I have tried some things. :

AT+COPS=?

always returns no operators.

Here is a stange thing too :

AT+CBAND=?

returns

INVALID_BAND_MODE, ALL_MODE

Any ideas ?
Thanks a lot !

 

[TiagoRibeiro]

Hello,
these sim cards you are using are new? If they try to activate them in a common cell phone first. And do tests with calls and sending messages. Make sure that the place where you have good signal from the telephone company.
After try this:


AT+COPS=0 To Force network registration.
Response sample: +COPS: 0,0,"vodafone IT"

AT+COPS? To Check network registration status.
Note: OK, the module is registered to GSM service.

Hope it helped you;-)

 

[hotkebab99]

Hello,
Thanks for the answer. However, it doesn't solve my problem.
No registration to network and always

AT+COPS=?
+COPS: ,,(0,1,4),(0,2)

AT+CBAND?
+CBAND: INVALID_BAND_MODE,ALL_BAND

I don't know what to do...

 

[TiagoRibeiro]

Hello,
Well, this shield SIM900 has antenna? Have you ever tried to send a text message or make a call? Normally when turning the module it registers in the telephony network automatically.