#4.3 GSM Module Installation
The GSM module is a bit more complex and can be problematic. In our case, the GSM module doesn't come with any documentation. We have created a simple connection scheme to connect the GSM with the RPI3 and the Touch screen.
About the installation, it is not easy to realize how to made it work. There is a physical switch to change between external power input and powering from the RPI3. If you choose to power the module from the RPI3 it will works but it will not be able to call or send an SMS since the RPI3 can provide enough energy and the module will shuts down if you try it. We have use an external battery with two outputs to power the GSM and the RPI3 independently.
In order to installing the module, We have to configure the serials. I used Minicom to test the connection. Also it was so helpful reading this blog to understand what are we doing.
The commands are:
$ sudo vi /boot/config.txt
There, add this in the last line:
enable_uart=1
Then, edit this file:
$ sudo nano /boot/cmdline.txt
In that file, this line should appear:
dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes root wait
Remove console=serial0,115200 from that line.
Reboot the device.
$ sudo reboot