I am facing this issue that I can't solve, I've been on this like 3 days and it is really frustrating!
I'm trying to test AT commands through port serial0, I've tried it in a python file and when i send the command it return the command in string instead of the "OK" response i am waiting for. I also tried to send command through screen/picocom but here the thing is that when I type the command and press enter it does nothing but return the prompt to the begining of the line.
I've followed many tutorials doing the same over these 3 days without success, I believe I have the right connections between the Raspberry Pi and the GSM module. My raspberry model is an RPi 3B model v1.2 and the GSM module is SIM808 EVB v3.2 if that helps.
import serial
import RPi.GPIO as gpio
port = serial.Serial("/dev/serial0", baudrate=9600, timeout=1)
port.write(b'AT'+b'\r\n')
rcv = port.read(100)
print(rcv)
that returns b'AT\r\n'
as response instead of the "OK"
that proves communication was successful.