SIM800C module, GPRS/GSM development board, Bluetooth TTS, DTMF, STM32 
The size is as big as a dollar coin, and the lithium battery power supply can be used as an intelligent wearable device, 
Supply voltage: 3.7V-4.2V 

This module is a tiny device almost the size of a dollar coin. It has a Quad-band GSM/GPPRS solution with an SMT type layout. It an ideal board for embedded consumer application.

This device can transmit voice, SMS and data information with very low power consumption. The board size is 17.6*15.7*2.3mm (LxWxH).

APPLICATIONS:

• 2G(GSM/GPRS )
  
• Quad-Band 2G
  
• SMT
  
• TTS
  
• Embedded AT
  
• MMS
  
• SSL Encryption
  
• Jamming Detection
  
• USB
  
• Bluetooth
  
• Serial interface
  
• SIM Access Profile
  
• RIL Driver
  
• RLS Monitoring
  
• Antenna Diagnostics