Sim800L Module is low cost, low form factor GSM module based on Simcoms SIM800L chipset. Sim800L module supports quad-band GSM and GPRS network.
This breakout board is perfect for application where size and cost is a constraint. Sim800l gsm module also supports quad band which means that it can work anywhere in the world. This low cost module is perfect for launching your next IoT project. Using this module you can almost make your own cellphone. 
 
Using this module you can:-
Send Text Messages (SMS)
Make or receive Phone calls
Connect to Internet via GPRS
TCP/IP
 
The main drawback of this module is works on 3.7 to 4.2 volts so you cannot power it directly through Arduino or Raspberry Pi. Moreover the sim800L GSM and GPRS module requires upto 2 ampere current so accordingly design your power supply. You can use a 3.7 volt lipo battery to directly power the GSM module.
 
You can communicate with SIM800l module via UART port, supports command including 3GPP TS 27.007, 27.005 and SIM COM enhanced AT Commands.
 
Features of SIM800L GSM Module:-
Quad-band 850/900/1800/1900MHz - connect onto any global GSM network with any 2G SIM (in the USA, T-Mobile is suggested).
Make and receive voice calls using a headset or an external 8Ω speaker and electret microphone.
PWM/Buzzer vibration motor control
AT command interface with "auto baud" detection
Send and receive SMS messages.
Send and receive GPRS data (TCP/IP, HTTP, etc.).
Scan and receive FM radio broadcasts.
Lead out buzzer and vibration motor control port.
AT command interface with "auto baud" detection.
Onboard IPEX socket that can be connected to external antenna.
Breakouts for external 8W speaker and electret mic if you don't want to use a headphone
Level shifting circuitry so you can run it with 2.8V to 5V logic.
Vibrational motor (buzzer) driver so you can have noiseless notifications
uFL or SMA connections for external antenna
Indicator LEDs for power and network connectivity
Standard SIM slides into the back
* Product Images are shown for illustrative purposes only and may differ from actual product.