This board version (49mm x 50mm) includes additional enhancements such as dual power supply options, SMA/IPX antenna interfaces, ESD protection on SIM card lines, and onboard reset. It is fully compatible with both 3.3V and 5V microcontrollers and supports 2G/3G/4G SIM cards (operating as 2G fallback).
Features
- Complete dual-band GSM/GPRS module: 900/1800MHz
- Supports Voice, SMS, Data, Fax
- Ultra-compact core size: 24mm x 24mm x 3mm
- Low power consumption with sleep mode (~10mA)
- Two onboard power options: 5V (VCC5) or 3.5x4.5V (VCC4)
- Optional auto-power-on or controlled startup
- Onboard SMA antenna connector + IPX mini connector
- Supports both 3.3V and 5V TTL UART
- ESD-protected SIM card interface (SMF05C)
- High-current capability for heavy data use (1A recommended)
- Compatible with 2G, 3G, and 4G SIM cards (2G fallback operation)
Onboard Resources
- Serial port circuit with voltage protection
- SMA female antenna connector + IPX mini connector
- Flip-type SIM card holder with SMF05C ESD protection
- 4 x 3.5mm mounting holes
- SIM900A hardware design fully follows manufacturer reference manual
Electrical Details
- VCC5: 5V DC input (requires 1A or more)
- VCC4: 3.5x4.5V input (ideal for Li-ion batteries)
- Standby current: Dozens of mA (configurable)
- Sleep current: ~10mA
- Module Board Size: 49mm x 47mm
- Core Module Size: 24mm x 24mm x 3mm
- Net Weight: 28g
- Package Weight: 38g
Pin Description
- GND: Ground
- SIMR: SIM900A RXD (TTL level, not RS232)
- SIMT: SIM900A TXD (TTL level, not RS232)
- RST: Reset pin, active LOW
- VCC_MCU:
- Connect to 5V when using 5V-logic MCU
- Connect to 3.3V when using 3.3V-logic MCU
- VCC5: DC 5V input
- VCC4: DC 3.5-4.5V input
Antenna Interface
- Default: SMA straight connector
- Optional: IPX mini connector
- Short and direct RF routing guarantees maximum signal strength
Supported Microcontrollers
- Arduino (3.3V or 5V logic)
- ESP32 / ESP8266 (3.3V TTL)
- STM32
- AVR, PIC, ARM MCUs
This board version (49mm x 50mm) includes additional enhancements such as dual power supply options, SMA/IPX antenna interfaces, ESD protection on SIM card lines, and onboard reset. It is fully compatible with both 3.3V and 5V microcontrollers and supports 2G/3G/4G SIM cards (operating as 2G fallback).
Features
- Complete dual-band GSM/GPRS module: 900/1800MHz
- Supports Voice, SMS, Data, Fax
- Ultra-compact core size: 24mm x 24mm x 3mm
- Low power consumption with sleep mode (~10mA)
- Two onboard power options: 5V (VCC5) or 3.5x4.5V (VCC4)
- Optional auto-power-on or controlled startup
- Onboard SMA antenna connector + IPX mini connector
- Supports both 3.3V and 5V TTL UART
- ESD-protected SIM card interface (SMF05C)
- High-current capability for heavy data use (1A recommended)
- Compatible with 2G, 3G, and 4G SIM cards (2G fallback operation)
Onboard Resources
- Serial port circuit with voltage protection
- SMA female antenna connector + IPX mini connector
- Flip-type SIM card holder with SMF05C ESD protection
- 4 x 3.5mm mounting holes
- SIM900A hardware design fully follows manufacturer reference manual
Electrical Details
- VCC5: 5V DC input (requires 1A or more)
- VCC4: 3.5x4.5V input (ideal for Li-ion batteries)
- Standby current: Dozens of mA (configurable)
- Sleep current: ~10mA
- Module Board Size: 49mm x 47mm
- Core Module Size: 24mm x 24mm x 3mm
- Net Weight: 28g
- Package Weight: 38g
Pin Description
- GND: Ground
- SIMR: SIM900A RXD (TTL level, not RS232)
- SIMT: SIM900A TXD (TTL level, not RS232)
- RST: Reset pin, active LOW
- VCC_MCU:
- Connect to 5V when using 5V-logic MCU
- Connect to 3.3V when using 3.3V-logic MCU
- VCC5: DC 5V input
- VCC4: DC 3.5-4.5V input
Antenna Interface
- Default: SMA straight connector
- Optional: IPX mini connector
- Short and direct RF routing guarantees maximum signal strength
Supported Microcontrollers
- Arduino (3.3V or 5V logic)
- ESP32 / ESP8266 (3.3V TTL)
- STM32
- AVR, PIC, ARM MCUs
