... GSV SIM900 GSM GPRS module, Quad-band, industrial standard Sim900,SIM900 Simcom wireless module,Simcom modules,modulesGeneral features * Quad-Band 850/ 900/ 1800/ ... (GSM 07.07 ,07.05 and SIMCOM enhanced AT Commands)* SIM application toolkit* Supply voltage range : 3.1 ... 4.8V ... rate (HR) – Full rate (FR) Interfaces* Interface to external SIM 3V/ 1.8V* analog audio interface* RTC backup* SPI interface ...