Using the ATK-SIM900A GSM/GPRS Module.

There are two different ways to use this module.

1. RS232
2. UART TTL

If you want to use this module directly from a PC, you’d go with the first method.

If you want to use the module through a microcontroller or some embedded microcomputer boards like the raspberry pi, you’d go with the second method.

Using the ATK-SIM900A through RS232

1. Connect the STXD → RRXD and SRXD → RTXD
2. Plug your RS232 cable to the DB9 connector on the board
3. Turn on the Module
4. Press and Hold the PWR_KEY for about 3 secs until the light starts to blink.
5. Plug the other end of the RS232 Cable to your computer and start sending AT commands.

Using the ATK-SIM900A through a Microcontroller

1. Connect the STXD → MCU RX pin
2. Connect the SRXD → MCU TX pin
3. Connect the GND → MCU GND
4. Turn on the Module
5. Press and Hold the PWR_KEY for about 3 secs until the light starts to blink.
6. Program the MCU to send AT commands through it’s serial port connected to the SIM900 Board.

Thats it, its that simple.