I would like to ask you for a bit of help. We are trying to build a fleet management system. As a GSM module we use SIM800L
We only need the GSM Module for Data Transfer, so we tested with RP3.
The problem is that it is very hectic/rare, sometimes it connects to the network sometimes it does not.
It is working very strange. My biggest problem is that it is giving me frequently the following message:
Why is it doing this?
We plugged/set it up as follow:
SIM800L - Rpi
vcc -> 5V
GND -> GND
RX/TX -> Tx/Rx
We tried to separate the power supply of VCC and GND both from a different power by 4,2 V, but the outcome is the same.
Interesting that if we do not plug them directly to RX/TX pins, instead of this we use a cable and connect to the USB port it works perfectly.
Why do we experience this? What is the reason of this? How should we connect them to each other? Thank you very much for your help in advance