If the closed ethernet network has a real computer on it, I would personal want to use that to talk to the SIM900, not an arduino. I wrote a SIM900 library for UNIX. I know there's one for Raspberry Pie.
If the closed ethernet network has a real computer on it, I would personal want to use that to talk to the SIM900, not an arduino. I wrote a SIM900 library for UNIX. I know there's one for Raspberry Pie.