Hi.
I have a problem with sim900. I buy in this shop online https://www.dfrobot.com/product-969.html

I try to connect to arduino Uno board. but the module not response.
I have a question.
1. I use J2 (5V, GND, TX, RX, and PowerUp pin) connect to Arduino Uno board. (5V, 0,1,9 Pin). I cant find why the a module not work.
2. What library can I used.
http://image.dfrobot.com/image/data/TOY0032/GSM%20Schematic.pdfThanks for helps