I'm using a SIM900A mini v3.8.2 GSM/GPRS board to make a phone call on certain conditions. I have connected the module through a CH340 USB to TTL converter to a PC (Windows 10) for testing. All connections are OK. I'm using a 5V 2A power supply so no power issues. The connection LED blinks after every 3 seconds, which means the network is connected. The power LED is on without any blinking.
I'm using the AT Command Tester software to test the SIM900A functionality.
- When I call a number it simply says
NO Carrier: Call dis-connected.
- It does not send or receive any SMS/voice calls.
Note: I have sufficient tariff/balance for SMS and voice calling, and the SIM is unlocked.
Different AT commands responses are as follows:
When I try to make a phone call its response is this:
When I send an SMS, the SIM900A response is as follows:
Now where is the problem? I also tested AT commands for voice calling in Arduino terminal manually but problem is same. Is there any 1st time settings or configuration that has to be set for successful communication, like APN, SIM provider settings, etc.?