hi everyone, i'm working on an Arduino Uno, with the Sim900 shield and is not getting connected to any network.
Things checked:
data:
+COPS: ,,(0,1,4),(0,2)
+CSQ: 0,0
idk what to do, please give me some light over my head :C
Can you share the link of the shiled that you're using? SIM900 operates at 5V, 2A. Since, you're using 12V adapter, let me ask you one thing. Does your shield have an on-board voltage regulator?
I just tried with 5v 4a ando same result
Hi
COPS in AT command is for operator selection, you need to download from google or other the AT command reference for SIM900, because you have a problem with this command
usually i use AT+COPS=0,1 for automatic selection of the operator in the zone. And always works well in SIM880 and A7672 (is the same manufacturer)
The CSQ is the parameter for quality of signal, that the first digit says the strong of the signal rssi and the second digit says about the BER (bit error rate).
So in this case, i see the CSQ is 0,0 this is by some things, bad area reception, bad antena connection, bad antena (change for other one), but also this can be the operator of your SIM card not support more in the area the 2G, or the chip is too old and need a newer SIM
Try change the SIM for another one, check if in the area is able the 2G of the operator, check the antena and the sma connector, download the AT command reference for the sim900 and check the commands for status and make test.
ps. The sim900 is discontinued, another solution is, change for one sim880 or A7600
well i test 3 simcards (different operators), 2 antenas and 2 GPRS SHIELD ARDUINO UNO, as i said, i test on a smartphone and sim has signal 
Is SIM modules allowed in your country? In 2021, we had a negative experience. The government decided to ban all unregistered mobile handsets. And whenever we tried to use SIM modules, the network detected those as unregistered handsets and block them. Make sure that this is not the case where you live.
I have another sim900 working with 12v, on a container, i really don't understand what's happening with this shields
And by the way, you been test with another arduino :D? when you have ruled out the impossible, whatever remains, however improbable, must be the truth xD
other problem is the voltage of the arduino and the voltage of the module, when one of them is unstable makes problems, check adding another source to the arduino
i just test the 4 chips and only 1 is getting signal on a smartphone, i try that one and it cannot reach any network :c
y test at+cband and i get INVALID_BAND_MODE, ALL_MODE idk what that means :C