Details:
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.
Consider:
Our experience is that the SIM800L below 3.8V doesn't really work.
For further information visit: datasheet
So your job is to provide at least 3.8V to the module (ideally 4V), a power supply which outputs at least 2A.
There is a red status LED which tells you what operation the SIM800L is in.
64 MS ON - 800MS OFF - SIM800L is not registered to the network.
64 MS ON - 3000MS OFF - SIM800L is registered to the network.
64 MS ON - 300MS OFF - SIM800l is in GPRS mode
If the SIM800L keeps restarting after about 8-10 blinks, it may be due to lack of efficient power supply.
If you don't get OK after AT, check wiring! If you have a multimeter, check continuity of the wires.
Check the connections of the wires and solder joints! The module will only work when blinking.
Package: 1x SIM800L GPRS GSM Module