[gentoo-user] [OT] laptop desktop serial connection don't work on one direction

[Kfir Lavi]

Hi all,
I have a problem connecting my laptop to my server at home with a serial
cable.
I have cable end for /dev/ttyS0 and 2 cable ends for /dev/ttyUSB0.
This lets me test the connection between all serial outputs.
Desktop1-minicom <-> Desktop2-minicom
works with all connections, i.e ttyUSB0 <-> ttyUSB0, or ttyS0 <-> ttyUSB0
and viseversa.
So when connecting 2 desktop computers everything works as expected.

The problem:
When I connect my laptop to any of those desktops, I get just one way
connection!
If I swap the sides of the cable, the one way connection switch side.
The laptop doesn't have ttyS0, so it have to be connected via ttyUSB0
When I swap sides, it is just between two usb dongles.

The usb dongles are PL2303 both sides.
Settings of minicom is 38400 8n1  Hardware Flow Control=OFF

Laptop setserial:
setserial -a /dev/ttyUSB0
/dev/ttyUSB0, Line 0, UART: 16654, Port: 0x0000, IRQ: 0
        Baud_base: 460800, close_delay: 0, divisor: 0
        closing_wait: infinte
        Flags: spd_normal

Desktop1 setserial:
setserial -a /dev/ttyS0
/dev/ttyS0, Line 0, UART: 16550A, Port: 0x03f8, IRQ: 4
        Baud_base: 115200, close_delay: 50, divisor: 0
        closing_wait: 3000
        Flags: spd_normal skip_test

setserial -a /dev/ttyUSB0
/dev/ttyUSB0, Line 0, UART: 16654, Port: 0x0000, IRQ: 0
        Baud_base: 460800, close_delay: 0, divisor: 0
        closing_wait: infinte
        Flags: spd_normal

I tried to add the skip_test but this seems to be not working.
I'm not sure what to do next.

Any help will be appreciated,
Thanks,
Kfir