Hey. I just bought New SIM900A V4.0, but there was no manual so I’m a bit confused of how to use it. I was looking for tutorials in google, but couldn’t find anything useful for my module particularly (I attached photo of it). Do anyone knows any tutorials related to how to connect it to Arduino Mega 2560 and some sample codes?
I would really appreciate any help 
The link in my signature includes using a SIM900 shield with the Mega.
Connect Rx to Tx, Tx to Rx and Gnd to Gnd. Does it have a voltage regulator and/or level shifters on board? 5 volts will be too much for it.
I don't think so. I added some pictures. Could please look at them:
http://postimg.org/image/h54yaodrh/
I have limited bandwidth so I won't be looking at the images provided I'm afraid.
There is 3.3 V out put on Arduino Board. On GSM shield, I can choose 5V or 3 V.
