SIM900 Strange Shield

Hello folks,

I am having serious trouble with a SIM900 shield, specifically this one:

I cannot find guidence on this specific shield, as there are no datasheets what-so-ever and the serial ports are not responding. I am using TeraTerm to listen to the device through an FTDI (the ftdi is working, I use it with my Arduino), before passing it to an Arduino.

Any advise on this one?

I have the serial comunication connected to the ftdi through uart (same GND, TX->RX and vice-versa). I am using TeraTerm to listen on the 9600 baudrate (tried on the 115200 too) so check for any signals, none came at this moment.

If you have any idea what can this be, I would be thankful!


I presume you followed the trail and found this


Yes, I had! And the problem for the communication is that the shield has wrong labels on the jumpers for TX/RX, so they are misplaced. Now I have sucessfully sent an SMS.

Thank you!