SIM900A Mini Module is built with Dual Band GSM/GPRS based SIM900A modem from SIMCOM. It works on frequencies 900/ 1800 MHz. SIM900A can search these two bands automatically. The frequency bands can also be set by AT Commands. The baud rate is configurable from 1200-115200 through AT command. The GSM/GPRS Modem is having internal TCP/IP stack to enable you to connect with internet via GPRS. SIM900A is an ultra compact and reliable wireless module. This is a complete 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.
Power supply You cannot power the module from the Arduino, as it is incapable of supplying the necessary peak currents. The Sim900 draws about 2A every so often. It’s not necessary to build a 2A supply, as a large storage capacitor on the power supply output will supply the current. I am using a small switch mode buck power supply to step down from an external 12V DC source to 3.3V, with a 0.1F 5V super capacitor on its output and that works a treat. I believe that a 1000uF low esr cap will also work, but I’ve not tried it. The photo shows the power supply with a 0.1F cap underneath.
- The onboard two set power supply interface VCC5 5V power supply, VCC4 interface, 3.5–4.5V power supply, optional power on self starting (default) and control start.
- The onboard SMA (default) and IPX mini antenna interface, SIM900A interface reserved reset.
- The size of the module is 49*50, all the new and original device.
- The computer can give early computer debugging USB module power supply, a very large amount of data under the condition of the recommended current more than 1A. Standby dozens of MA data can be set to provide dormancy, dormancy of 10MA low power. Support 2, mobile phone 3,4G card
- The serial port circuit: support for 3.3V single-chip microcomputer. TTL serial port support.
- 3.3 and 5V single-chip microcomputer.
- Built-in SIM Cardholder.
- The SIM card circuit to increase the SMF05C ESD chip.
- Antenna circuit: guarantee short and straight, so as to ensure the signal strength.
- Two power supply interface: VCC5, 5V DC above 1A. Computer 5V power supply can be an early computer USB. DC long data circuit over larger recommended 5V1A. VCC4, 3.5–4.5V power supply, ibid., suitable for a lithium battery.
- Low power.
- The module is the best application to design a graphic for Voice call and SMS application.
- Some IoT applications, mostly in an emergency have the module.
- The location trancing system also uses SIM900A.
- SIM900A can use for mobile communication.