Quad-Band 850 / 900/ 1800/1900 MHz-would work on networks in all countries across the world. GPRS multi-slot /8; GPRS mobile station class B. Control via AT commands-Standard Commands: 07.07 & 07.05 | Enhanced Commands: SIMCOM AT Commands. Short Message Service-so you can send small amounts of data over (ASCII or raw hexadecimal). Embedded /UDP stack-allows you to upload data to a web server. supported. Selectable serial port. Speaker and Headphone jacks. Low consumption-1.5mA(sleep mode). Industrial Temperature Range--40 Celsius to +85 Celsius.Application Ideas: M2M (Machine 2 Machine) Applicatoions. Remote control of appliances. Remote or a Wireless Sensor Network. Vehicle Tracking System with a GPS module. Compliant to phase 2/2+Class 4 (2 W @ 850/900 MHz)Class 1 (1 W @ 1800 / 1900MHz)CautionsMake your is unlocked.The product is provided as is without an insulating enclosure. Please observe ESD precautions specially in dry (low humidity) weather.The factory default setting for the GPRS Shield UART is 19200 8-N-1. (Can be changed using AT commands).Interface Introduction select-select the supply for GPRS shield(external or 5v of) -connected to external 4.8~5VDC supplyAntenna interface-connected to external antennaSerial port select-select either software serial port or hareware serial port to be connected to GPRS ShieldHardware Serial-D0/D1 ofSoftware serial-D7/D8 ofStatus LED-tell whether the of SIM900 is onNet light-tell the status about SIM900 linking to the netUART of SIM900-UART pins breakout of SIM900Microphone-to answer the phone callSpeaker-to answer the phone callColour:As shownMaterial: PCBPackage Contents:1 x SIM900 Development Board1 x AntennaOnly the above package content, other products are not included.Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.