multiple SIM300 modems with single micro controller

[dhanraj_kmr]

Hi All,
I am planning to design a ARM based product which would consist around 20 GSM modems with 20 SIM cards. SIMCOM website shows the SIM900 supports only I2C and by default I2C is not enabled and there should be another firmware.

And another document shows that SIM300 supports SPI interface which means i can achieve my concept.

So kind of needed some confirmation from users who has used multiple modems with single micro controller.
I hope my question is clear, if its not please let me know i will brief it more.

I want to know which modem supports SPI interface or I2C interface which could serve my requirement.

Thanks all for going through my question.

 

[mathespbe]

You can use modems which can connect through SPI or I2C. Explain your exact need. So that some solution can be found...

 

[dhanraj_kmr]

Hi,
I want to send bulk SMS. This is my application.