Hello all,
Recently i bought the epalsite.com Sim900 shield. Yesterday my module was receiving SMS messages and phone calls, but after some bug fixes for other parts of the application suddenly i couldn't receive any SMS messages or calls. I followed two different approaches but neither worked.
My first approach is turning on the module and sending a SMS to it. Then after a while i'm checking the memory status, but that is returning 0 messages all the time. After that I placed the SIM card in a real phone, send a message to this phone and after receiving it switch the SIM card back to the module. Then I check the memory status again and I see 1 message. So my code is working fine...
In my second approach I tried to send all SMS data to the serial immediately. (AT+CNMI=2,2,0,0,0) This worked to yesterday, but now i don't get response anymore.
The same goes for receiving phone calls, just can't see any information on my screen (like RING or HUNG UP)
Important to notice is that everything else is working perfect! I can make a phone call, send SMS messages and execute all kind of AT commands without any errors.
Can somebody please help me out, really stuck at this one. Maybe there is some kind of AT command that is blocking all incoming traffic? Or maybe a hardware issue?