From the product manual / reference guide it looks like SIM900 / SIM900A is already equipped with 12 GPIOs.
But could not find information on how to use these GPIOs to control relays directly, instead of routing them through additional MCUs.
Most examples on the net (such as this) use the SIM900 just for read/write, completely ignoring its GPIO capabilities.
Any pointers on how to use the GPIOs of SIM900 as control signals directly - please help.
Thanks in advance.