SIM900 Module 4-band Development Board For GSM GPRS SMS Wireless Data Over TC35i

nullInstructions for use:1. Computer debugging USB--TTL is enough. The power supply of this module is: 5V-26V, 5V 2A power is recommended. After plugging in the motherboard, the power supply must be able to provide 2A. The reason is that GPRS Shield requires a maximum of 2A for the startup current and the maximum peak current at work, but the USB port cannot provide such a large current, so an external power supply device must be provided. The 3.7--4.5V power supply from the other power supply port is suitable for lithium battery power supply. The serial port is perfectly compatible with the microcontroller. The TTL serial port is compatible with 3.3 and 5V microcontrollers.2. Make sure your SIM card is not locked3. The baud rate of GPRS Shield communication is preferably 19200 bps 8-N-1 (the default baud rate of GPRS Shield is automatically paired)Features:1. Quad-Band 850 / 900/ 1800 / 1900 MHz - would work on GSM networks in all countries across the world.2. GPRS multi-slot class 10/83. GPRS mobile station class B4. Compliant to GSM phase 2/2+5. Class 4 (2 W @ 850 / 900 MHz)6. Class 1 (1 W @ 1800 / 1900MHz)7. Control via AT commands - Standard Commands: GSM 07.0707.05 | Enhanced Commands: SIMCOM AT Commands.8. Short Message Service - so that you can send small amounts of data over the network (ASCII or raw hexadecimal).9. Embedded TCP/UDP stack - allows you to upload data to a web server.10. RTC supported.11. Selectable serial port.12. Speaker and Headphone jacks13. Low