I am trying to get a SIM7600E-H-4G-HAT running on my Raspberry Pi 3B+, but it is not working. Here is what I've done so far:
Inserted my SIM-Card, connected the antenna to Main, connected the entire hat via GPIO pins to my Pi without any USB cable connected to that hat. I left the two yellow jumpers factory-default like, centered just as pictured in the manual.
I booted the raspberry, set via
raspi-configthe serial options as described in the manual (no, then yes).
sh /home/.../sim7600_4G_hat_initto rc.local
Rebooted, installed minicom, started
sudo minicom -D /dev/ttyS0and nothing happens and it does not even react on any keystroke. I even compiled the bcm2835 directory and the phoncecall-demo. When I try to
sudo ./Phonecallit says
Failed to get byte count on serial.
Both LEDs shine red permanently. What am I doing wrong?