First of all, you connected the USB/TTL cable wrong. You should not connect the red line. It must be connected as shown here: connect USB to TTL (RS232) serial cable.

I do not know Manjoro, but on Raspbian you have to add this line to /boot/config.txt:

enable_uart=1

and you (user pi) should be a member of group dialout so you do not have to use sudo.

Using screen is normally OK but it is a fairly complex program and at first not made to connect to serial lines. I like to use a simple program tio (terminal IO) that is just made for serial connections like this. Just install it with:

mngmt ~$ sudo apt install tio
mngmt ~$ tio /dev/ttyUSB0   # be member in group dialout

If you still get a black screen then you have a problem with the hardware.

First of all, you connected the USB/TTL cable wrong. You should not connect the red line. It must be connected as shown here: connect USB to TTL (RS232) serial cable.

I do not know Manjoro, but on Raspbian you have to add this line to /boot/config.txt:

enable_uart=1

and you (user pi) should be a member of group dialout so you do not have to use sudo. You must also have an entry console=serial0,115200 in /boot/cmdline.txt, so it looks similar to this (don't touch your other settings):

console=serial0,115200 root=PARTUUID=738a4d67-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait quiet

Using screen is normally OK but it is a fairly complex program and at first not made to connect to serial lines. I like to use a simple program tio (terminal IO) that is just made for serial connections like this. Just install it with:

mngmt ~$ sudo apt install tio
mngmt ~$ tio /dev/ttyUSB0   # be member in group dialout

If you still get a black screen then you have a problem with the hardware.

First of all, you connected the USB/TTL cable wrong. You should not connect the red line. It must be connected as shown here: connect USB to TTL (RS232) serial cable.

I do not know Manjoro, but on Raspbian you have to add this line to /boot/config.txt:

enable_uart=1

and you (user pi) should be a member of group dialout so you do not have to use sudo.

First of all, you connected the USB/TTL cable wrong. You should not connect the red line. It must be connected as shown here: connect USB to TTL (RS232) serial cable.

I do not know Manjoro, but on Raspbian you have to add this line to /boot/config.txt:

enable_uart=1

and you (user pi) should be a member of group dialout so you do not have to use sudo.

Using screen is normally OK but it is a fairly complex program and at first not made to connect to serial lines. I like to use a simple program tio (terminal IO) that is just made for serial connections like this. Just install it with:

mngmt ~$ sudo apt install tio
mngmt ~$ tio /dev/ttyUSB0   # be member in group dialout

If you still get a black screen then you have a problem with the hardware.