I managed to connect the serial cards to a raspberrypi to /dev/ttyUSB0 and /dev/ttyUSB2. Then I startet socat:
socat -d -d -d /dev/ttyUSB0,raw,echo=0 /dev/ttyUSB2,raw,echo=0
This couples the serial devices like the crosscable before. KillTheBit was running.
Next step was to use two rasperrypis. I connectd a terminal to one at /dev/tty/USB0 and the lab8/e to the other respberry at /dev/ttyUSB0.
Then at terminal host: socat -d -d -d /dev/ttyUSB0,echo=0,raw tcp4-listen:4711
and at lab/8 host: socat -d -d -d /dev/ttyUSB0,raw,echo=0 tcp4-connect:192.168.0.100:4711
And it was possible to run OS/8 in this terminal.
So if someone wants to connect to my lab/8 over the internet, well, why not? We could play KillThe Bit over the net! We have to exchange the IP's and drill a whole into the firewall roter, but then...
Who wants?