SIM800 GSM GPRS MMS, SMS, STM32 development board for UNO, offers the following advantages:

• Serial interface, supports TTL serial for STC89C51/52, STM32, and MSP430.
• Requires only 3 to 4 pins for control.
• Antenna circuits: three common antenna interfaces (SMA) with non-soldering capability.
• Two power supply methods: DCIN GND, 5V - 18V DC; 3V8 GND, 3.5-4.2V suitable for lithium battery power supply.
• Audio interface: addition of 3.5MM audio for easy voice calls and announcements.
• SIM booth: new main metal MICRO socket, durable and strong.
• LED indicators: two essential LED indicators to show the operating status of the module.
• PCB: each interface has a printed label, facilitating secondary development by fully following the SIM800/A design manual.