... SIM900A Based on Simcom module SIM900A With TCP/IP stack 900/1800MHZ STK,internet, data, sms, GPRS MODEM RS485 SIM900AProduct descriptionGeneral Features ... sensitivityAlways on-lineOutput PowerClass 4(2W @ 900MHz)Class 1(1W @ 1800MHz)Input voltage 7V-36V DCInput current 1A-2AStandby current: 56mAWorking ...