AT Command to control GPIO
M2M application developers can use the General Purpose Input Output (GPIO) pins for various types of controls. Module vendors generally provide proprietary AT commands to read/write the GPIOs.
SIMCOM provides AT commands to control the GPIO,
Above response indicates that the AT command support set/read operation (0-1), it can set any of the 12 GPIOs (1-12), it can be configured to input/output/keypad (0-2) and the actual value can be set to 0 or 1 (0-1)
Set GPIO 1 as input,
Read GPIO 1