Smallest SIM800L GPRS GSM Module Micro SIM Card Board Quad-Band Onboard
Package Includes: 1 x SIM800L GPRS GSM Module Card Board Quad-band Onboard TTL Port
TTL serial port, directly connect to the microcontroller.
Charge the module, it will automatically boot and search for network.
Onboard signal indicator will always be flashing. It flashes slowly
when there is a signal. it flashes quickly when there is no signal.