This is mini GSM / GPRS core board based on SIM900A. It supports dual-band GSM/GPRS network, available for GPRS and SMS message data remote transmission.
The board features compact size and low current consumption. With power saving technique, the current consumption is as low as 4mA in sleep mode.
It communicates with microcontroller via UART port, supports command including GSM 07.07, GSM 07.05 and SIMCOM enhanced AT Commands.
p.s: Network signal only blink whle SIM card inserted.
Normally will need 30 seconds to get a network signal.