ICOMSat Sim900 / Mega2560

Hi,

I am hoping to get some help. I am working with the uno and icomsat v1.1. I used the icomsat as a shield to the uno and connected directly to my laptop. I used the libraries from competefornothing.

When I ran the serial monitor, it says :

GSM Shield testing.
ERROR: SIM900 doesn't answer. Check power and serial pins in GSM.cpp

status=IDLE

Could I get some advice on this please?

Thank you...