Thanks for the help. It shows a bit of info. Sadly DTR is disconnected and I don't trust my soldering skills to connect a wire myself.
Where did you find it? Maybe there's more there.
I use the DTR on my SIM900. I use a custom made interface board to interface the MEGA2560 and the SIM900. In place of the interface board, You can use a small jumper to an unused pin of the MEGA2560 and control the DTR with that. Any questions, please reply.