- SIM900A is dual-band frequency : 900/ 1800 MHz highly integrated GSM/GPRS module; Note: SIM900 (without “A”) is working for quad-band frequency (expensive model) usually used for Europe and USA region, SIM900A is good for Indonesia region.
- SIMCard Flip models easy to put/ release of SIM card;
- DC power supply port available (can accept DC adapter with 5 Volt DC, with minimum 1A current)
- Communications :
TTL level serial interface : Using the serial module to send AT order to the GSM module, then it can control the module to send message , make a call and connect to the GPRS. You can connect the serial port of the USB TO TTL and the MUC to the serial port of this module. Pay attention to the level of the interface. See this explanation :
- If the level of the interface is 3.3V, then we can connect it with the 3VR (Receiver) and 3VT (Transmitter) directly.
- If the VCC_MCU with the voltage equal with the serial level, connect the serial with the OVR (Receiver) and OVT (Transmitter), then it can match other level interfaces. They have common GND. See this video for complete tutorial : https://www.tindie.com/products/ICStation/sim900-gsm-module5253/
- Notice to use (AT Command Test using Hyperterminal) :
- Plug External Power (9Volt DC Adaptor – recommended, you can purchase additional Item No. KR20083)
- Using USB to Serial (you can purchase additional Item No. KR06046)
- Connect between USB to Serial/ TTL Module with SIM900A Module (only 3 pin = port Rx-Tx, Tx-Rx, Gnd-Gnd)
- First turn on the external power/ adaptor first, you will see PWR LED & D4 LED (at bottom SIM900A modules will ON), after some seconds D5 LED (bottom module) will turn ON, and D4 LED (top module) will blinking – at this state is mean SIM900A is ready to receive AT command instruction.
- Second, plug USB to Serial/ TTL module to USB port
- Run Hyperterminal software and check standard setting serial communication using 9600bps, stop bit 1, N
- Last, you will showed with blank page with underscore cursor, just typing “AT” then ENTER, a new row below will occur with “OK” text showed.
Low Cost SIM900A GSM Module