title: My arduino sim 900 won't send sms or call
body: <p>I have arduino uno and this SIM900 <a href="http://www.ebay.com/itm/SIM900-GPRS-GSM-Board-Quad-Band-Module-For-Arduino-Compatible-High-Quality-New-/331463813989?pt=AU_Gadgets&amp;hash=item4d2cc86b65" rel="nofollow">gprs/sim</a>. I followed this <a href="http://tronixstuff.com/2014/01/08/tutorial-arduino-and-sim900-gsm-modules/" rel="nofollow">tutorial</a> and everything was fine. The code was properly updated and led lamps was properly shining, but it won't send sms or call someone. Then I trid code from this <a href="http://htt://linksprite.com/wiki/index.php5?title=SIM900_GPRS/GSM_Shield" rel="nofollow">site</a>, but my serial monitor won't recognize messages t or d. Nothing happens. What do I do? Thanks.</p>