Sim900 Mini V4.0 Wireless Data Transmission Module Gsm Gprs Antenna C83

Power can be provided via the computer's USB port for early debugging; for large data transfers, a recommended current of over 1A is required. The module can be configured for low-power idle mode with 10mA standby current. Supports 2G and 3.4G SIM cards.
Serial connection port circuit: compatible with 3.3V microcontrollers. Supports TTL serial ports for both 3.3V and 5V microcontrollers.
SIM card circuit: includes an SMF05C ESD protection chip.
Antenna circuit: designed to be short and straight to ensure signal strength.
PCB screen printing: clearly marks each interface. The SIM900/A design strictly follows the official design manual.
Two power supply interfaces:
- VCC5: 5V DC, recommended current >1A. Can be powered by computer USB.
- VCC4: 3.5-4.5V DC, suitable for lithium batteries.
Check all pin cables.
Single TTL level, compatible with 3.3V and 5V.
Two antenna interfaces: default SMA straight connector, compatible with IPX mini antennas.
Audio interface: microphone and speaker form.
Control interface pin description:
GND - Ground
SIMR - SIM900 RXD, TTL level, cannot connect directly to RS232 level
SIMT - SIM900 TXD, TTL level, cannot connect directly to RS232 level
RST - SIM900 reset, active low
VCC_MCU: when the SIM900 module communicates with a 5V TTL level, connect this pin to 5V DC; when communicating with a 3.3V TTL level, connect this pin to 3.3V DC.
VCC5 ---- DC 5V INPUT.
VCC4 ------ DC 3.5-4.5V INPUT