Chip:SIM800L
Voltage:DC3.7-4.2V(1A current peak)
Module size:2.5 x 2.34cm
TTL serial port for serial port, you can link directly to the microcontroller. No need MAX232 Power module
automatically boot, homing network Onboard signal lights all the way. It flashes slowly when there is a signal,
it flashes quickly when there is no signal.