Hello everyone I'm using the Sim900A when using the AT+CREG? it gives 0,0 any solution ??
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initial guess = power for the sim900A module is not correct
Does your country/network still support 2G mobiles.
Sorry sir for the status I posted I will improve it.
I use an arduino M0 board, when I send the AT command to the Sim900A module it gives an OK answer which proves that the communication between arduino and the module is good only when I use the AT+CREG? command to check if there is a connection it gives 0,0
Yes it does and I'm using Ooredoo sim card
it means the serial communication is established correctly not that the module is "good". AT does not require lots of power from the SIM900. A failing AT+CREG might mean that the device did not get enough current to connect for example, or the SIM card is not inserted in the right way, or that you don't have GPRS capability in reach etc
without more information on the circuit and power and test conditions it's hard to provide any relevant guidance. if you have blinking leds on your module, look up in the documentation what the blinking pattern means.
Don’t forget @J-M-L’s suggestion.
The modems typically require 500mA or more while operating, but can pull as much as 2A while negotiating a connection or transmitting in a weak coverage area.
you can check the SIM with
AT+CIMI returns IMSI of the SIM card
AT+CCID returns the SIM ID number
AT+CNUM returns your telephone number
what does AT+CSQ return?
+CSQ: 0,0 indicates you have no signal
is your antenna connected OK?
are you in a building which is screening the signal? try by a winow
does a mobile phone work with the SIM?
I often use this sim for a 4G connection and it works normally in my phone and the antenna is OK. I'm using Ooredoo which is international
the SIM900A power supply is 5V the antenna is in place and the LED is blinking every 1 second
what amp capability ? 2A would be great
do you have GPRS capability in your region of the world? (it's getting switched off in more and more places)
I'm living in algeria and we use 900MHz
2 amps or not ?
can you post a picture of your circuit / device ?
Rx and Tx pins are used by the USB/Serial monitor so you can't share them with the GPRS module
the 5V pin of the Arduino cannot / should not provide 2A
use a dedicated power supply for the module. 5V 2A
connect the GNDs
use software Serial and pin 2/3 for example to discuss with the module
At first make sure that SIM900A is supported in your country. For example, in my country the Telecommunication Regulatory commission has blocked all unregistered handsets. So, whenever a SIM900 tries to connect to the network, it is detected as an unregistered handset and rejected by the network. We can no longer just buy a SIM900 and use it now. Be sure about the ruling in your your country. If you are allowed to use a SIM900, please always power it up with a separate 5V, 2A adapter. Powering it up from arduino board's VCC and GND will not work.
SoftwareSerial doesn't work the arduino M0 I can't use it I'm using Serial1