SIM900 is a complete Quad-band GSM/GPRS module in a SMT type and designed with a very powerful single-chip processor integrating AMR926EJ-S core, allowing you to benefit from small dimensions and cost-effective solutions.
Featuring an industry-standard interface, the SIM900 delivers GSM/GPRS 850/900/1800/1900MHz performance for voice, SMS, Data, and Fax in a small form factor and with low power consumption. With a tiny configuration of 24mm x 24mm x 3 mm, SIM900 can fit almost all the space requirements in your M2M applications, especially for slim and compact demands of design.
(1) stable and reliable power supply, the board use bridge pile of rectifier filter, the input voltage widely use 9 VDC-12 VDC , at the same time, there is 2 A fuse on board , the board will be safely and reliable.
(2) high current power supply design using the special power IC–MIC29302, to ensure stable power supply. Why we have not use LM7805? the 5V output voltage very close to the module’s upper critical point, so work long time, poor stability, it’s dangerous, the maximum output current of LM7805 is 1.5A and MIC29302′s maximum output current up to 3A, in poor signal areas, in order to search for network signals, the module will enhance the their transmit power, then the current consumption is very large.
(3) 1 channel LED indicator lights: it indicate the SIM900 work status.
(4) RS232 serial communication: PC send GSM module AT command by RS232 port;
(5)1 LED: a power indicator.
(6) 9 v dc power input: take the power indicator.
(7)on-board microphone, handset interface: users can connect with the microphone and speak on the board.