GPRS seedstudio not responding


My GPRS module from seedstudio is not working properly with my arduino Mega.

We try to send AT commands to it through the D7/D8 (newsoft serial) and using an hardware UART (uart 1).
And the SIM900 doesn´t seem to respond to anything.

We have another module from sparksfun SM5100B and it seems to work with the hardware UART so i suppose that this is not an hardware problem on the Arduino Mega side.

I have searched on the forum and i found a big thread ( about the problem, but i didn´t understood if someone got to a solution for this problem.

Is this a problem with one lot of modules or is it a recurrent problem?

Does someone has any idea?

Best regards



We have done further testing and we were able to obtain the same behaviour as guan in the other thread ( ).
Send SMS, but not able to receive any kind of confirmation or answering to our sent AT commands…

At the moment no one is answering in the forum…, but i would like to know if this is a problem in a lote of fabricated boards or if it is some strange problem that is happening that as a solution.

Can someone help me/us to solve this issue? Can someone from seedstudios give some support please?

Best regards