Using one of those FTDI kenwood adapter programming cables. My gut feeling is no. It would be nice for things like sending/receiving SSTV images.
I am able to transmit if I use a double ended male 3.5 mm cable in the microphone hole of the radio and the headphones hole in my computer, but I have to hold down the PTT button. Also I have to turn the volume on my computer down a lot or else it is distorted. I suspect this has something to do with “line out” versus “headphones” voltage levels (I recall seeing some YouTube video discuss this).
No, you need an audio interface such as a Signalink or Digirig.
You could also make a simple interface with a couple of audio cables connected to your sound card. You will need an L pad to reduce the line level from the computer down to microphone level for the radio. For some modes like SSTV, you can use the VOX function on your radio to transmit, Many other modes will need some sort of PTT control because VOX will be too slow.
