I have a SIM800L Version 2 connected to an Arduino Uno for receiving SMS and making calls. I am powering the SIM800L with a 12V 2A power supply, stepped down to 5V using a buck converter. The SIM800L often blinks 7 times rapidly, then pauses for 1 second with no lights, and starts blinking 7 times again. I executed AT and AT+CSQ commands, and AT returns OK, but CSQ usually shows 0. Sometimes, when it connects, CSQ shows 30. And simetimes it work very well for few days.
Can anyone help me diagnose the issue?
THANK YOU !!