Connect the serial port, 180 degree DIN socket on the Apple IIc to a RS232 to USB adapter. Plug the USB into the Pi, or to your Powered hub.
To test if it is working. You need to install the “screen” program, if it is not on your system already.
sudo apt-get install screen
On the Apple IIc, use the Utilities disk and choose “Apple Modem 1200 baud in slot 2”. You can change this later, once you have got it working.
If you have not got the utilities disk for the IIc, download it off the internet and make it into a real disk using ADT.
dmesg | grep tty
You’ll see something like:
usb 4-1: pl2303 converter now attached to ttyUSB0
which proves it’s working!
sudo screen /dev/ttyUSB0 1200
Now, what you type on your Apple II will appear on your Linux machine!!